What To Look For When Buying A Gem
For many people who are new to the world of coloured gemstones, the prospect of buying a significant gem can appear quite daunting at first and after a little while downright confusing and overwhelming. It won’t take long to discover that prices for gems which to all appearances seem the same can vary quite significantly between vendors. Where diamonds are relatively familiar and commonplace with prices highly regulated, coloured gems for the most part are not.
Coloured gems have been revered throughout history and in every culture for their rarity and otherworldly beauty but over the last century or so have been pushed into the shadows somewhat by diamonds. As a result many people know very little about these beautifully hued gems with the exception perhaps that rubies are red, sapphires are blue and emeralds are green, that sort of thing. Beyond that things start to get a bit sketchy. The good news is that in today's high definition world coloured gems are thankfully experiencing a long overdue renaissance.
In this guide I touch on a few basic things that I think you need to know and look for when buying a gemstone. Each of these are entire subjects in their own right and there are some very good books, online forums and information available should you wish to dive more deeply. I would advise that if you are going to spend decent money on a gemstone, do some research first and get some knowledge about the type of stone you are looking at purchasing.
Even at a basic level, being able to differentiate between a poor quality gem and a fine one is a skill that can serve you well and will save you money and disappointment in the long run. Like all things in life, its experience that counts and the more gemstones you look at the better you get.
Table of Contents
The Basics
Before we begin anything lets define some basic gem terminology.
TABLE : The top flat surface of the gem.
CROWN : The top part of the gem above the girdle.
GIRDLE : The belt or band that goes around the middle of the gem.
PAVILION : This is the bottom part of the gem beneath the girdle.
CULET : The lowest point or bottom edge (keel) of the pavilion.
FACETS : The polished (usually flat) surfaces of the gem.
MEETPOINTS : Literally the points or corners where facets meet.
Its All About Light And Angles
This is what it boils down to... light! The essence of the gemcutter's art is to get as much light as possible to return back up through the top of the stone to your eye and the critical part of this is getting the angles right. See the light, see the colour.
The first illustration shows an ideally cut gem. The angles and proportions are correct and light returns back out the top to the viewing eye. This is what you want! You want the light entering down through the crown and table to reflect off the pavilion facets, bounce around and exit back out the top. The more light that does this the better and more brilliant the gemstone will be.
On a subtle level, you can see that the proportions and angles are more pleasing to the eye. This might be something that takes a little practise to dial in the eye to perceive but once you recognise what you're seeing, you've got it.
The second illustration shows a gem with a pavilion that is too shallow. The angles on the pavilion are less than ideal and light escapes out the bottom. This will create what's known as a window or fish-eye effect. Shallow pavilions are something that you will often see with commercial cut gems and is perhaps the most common fault you’ll encounter. However there are certain designs and cuts where a shallow pavilion is intentional, such as with portrait cuts, but for the vast majority of gems this is considered a negative.
The angles on this gem are too steep and light escapes out the side of the pavilion. This can create an area of darkening, sort of like a shadow, inside the stone called an extinction where little or no light is returned back to the eye. This is also considered a negative and has the additional drawback of making the gem sit overly high in the setting. The best thing to do with such a gem is to recut the pavilion to more ideal angles.
Correct angles on the pavilion and crown affect how much light is returned and thus its brilliance and overall beauty. Now, just to complicate matters, each type or family of stone (ie, sapphire, quartz, topaz, garnet, tourmaline, diamond, etc) has a different set of critical angles which determine the most optimal angles for faceting in order to return the most light. Unless you are planning on cutting a stone yourself you don't really need to worry about what these critical angles are exactly, only that they exist and they impact on what the eye perceives. These angles are something that the gemcutter needs to know as it directly affects the designs that can be used on a particular type of stone and how well they perform. It is integral to good quality gemcutting.
The Cut
In the world of coloured gemstones, COLOUR is king but the CUT is the power behind the throne.
Many people are familiar with the four "C's" when it comes to grading diamonds: Colour, Clarity, Carats and Cut. Great care and attention is paid to the cut when diamond gems are being made. In the marketplace your attention will always be directed to the quality of the cut. Unfortunately, when it comes to coloured stones in the mainstream commercial marketplace, for reasons many, varied and baffling, the four "C's" no longer seem to be so important, it's more like two and a half "C's". The Cut is quickly discarded and Clarity is diminished. It's all about Colour and Carats and this, in my opinion, does the industry and the buying public a great disservice.
There are essentially two types of gemcutting out there in the marketplace : Commercial and Precision.
Commercial Cut
By far the vast majority of gems that you see for sale in the retail sector, by jewellers and gem vendors, on ebay and all over the internet have been commercially cut. In large part this takes place in the cutting "houses" and factories of Asia (Thailand, China, India, Sri Lanka and elsewhere) and Africa.
To be fair, there is some very good quality commercial cutting being done by some operations but unfortunately most of it is pretty average and that is being kind. Quite a lot of it is very poor indeed.
You will still hear the term "native cut" when it comes to describing very poorly cut gems. It's a term I personally try to avoid using but it originates from the fact that in the past and even today, many gems were and still are cut using very basic equipment in very basic conditions by people not paid very much at all and with minimal attention to detail or quality. If someone describes a gem to you as being "native cut" then you should have an idea of what to expect. Ironically, you can come across some very stunning gems with incredible colour and clarity, it’s just a shame that they’ve let down by the cutting. For the savvy buyer, such gems can represent a smart investment as these gems can be recut and their potential fully realised and value dramatically increased, but you do need to know what to look for.
The primary goal of mainstream commercial cutting is carat weight! Pure and simple. The more weight in gems produced from rough stones the more money made. Carats = $$$. It's a very simple equation. Gems are relegated to being just a commodity. Exceptional stones may be singled out for more care and attention and given to more experienced cutters to handle but by and large most of the stones are cut solely to get the heaviest gem they can. Minimal attention is paid to things like correct angles, symmetry, polish, facet designs, and other considerations. The objective is not to cut the most beautiful gem they can, it is to cut the heaviest. A beautiful gem is not the goal. Cutting a gem to correct angles is anathema to this style of cutting because correct angles will usually result a lighter stone and that means less money. It is a concept completely alien and incomprehensible.
Shapes and designs are generally limited to a very basic selection of rounds, ovals and cushions, and usually feature a poorly executed step cut or checkerboard pattern on the pavilion which do no favors to the gem. Commercial cutters are not paid to be inventive or expressive in the work they do for to do so would involve the luxury of time. They are paid to churn out as much as possible as quickly as possible. The cutting factories have large volumes of rough stones coming in that they need to convert into gems.
Above is an illustration of a commercially cut blue sapphire from Ceylon (Sri Lanka). This is a stone that might once have been called native cut. I have indicated various aspects that relate directly to the poor level of cut quality and these are things that you will, should you look closely at other gems, see with your own eyes. When inspecting gems I recommend using an eye loupe or a magnifying glass. Make sure you have good lighting and don't be pressed or rushed by the vendor. Take your time and don't be afraid to ask questions. A gem like this is also a nightmare for a jeweller to set. However, as I mentioned earlier, it is a good candidate for recutting. Gemcutters like myself will always keep our eyes open for gems like this as we sort of consider them preformed and we can see what the clarity and colour is.
Precision Cut
Where commercial cutting concentrates on return weight yield, precision cutting is at the opposite pole and focuses more on the quality of the cut in order to make the gem look as beautiful as it possibly can. Don't get me wrong, return weight yield is still very important and we try to maximise it as much as possible, but as precision gemcutters we tend to pay more attention to details like correct angles, orientating the rough to achieve the best colour, selection of good well-suited designs, nice even facets and meetpoints, achieving an excellent scratch-free polish, getting a high degree of light return and really showing off the colour. We want to realise the potential within each gem we handle. For me personally, it’s about honoring the stone.
This does comes at a price and that price is time. Where a gemcutter in a cutting "house" might churn out dozens and dozens of gems in a day, a precision gemcutter might produce only one, two or maybe even three on a good day. There are those that can do more, and those that do less. Each precision gemcutter has their own way of doing things and generally needs to factor in time each day to do the myriad other necessities of running their own business. How long it takes to cut a gem depends on many considerations such as the size and type of the stone being cut, the complexity of the design, flaws and inclusions, etc.
Precision cut stones are usually quite bespoke in nature. Gems are often commissioned by a client or jeweller and can be cut to specified sizes, designs and colours. They are in effect "tailor made" or "made to order" gems. The result is a gem that is full of life and colour, dazzling, special and unique. They look absolutely beautiful and are a testament to the gemcutters’ skill and expertise.
The ironic thing is that, given two rough stones such as a couple of blue sapphires of an equivalent quality which would produce the same length/width size, the precision cut gem which would be lighter in carat weight can actually demand more per carat then it's heavier, poorly cut commercial sibling. An additional benefit is that the beautiful precision cut stone will in all likelihood sell quicker and look so much better in the setting. It's a lot easier to sell a beautifully cut gem then a poorly cut one.
The money supposedly "lost" in a reduced carat weight is more than made up for by the beauty and quality of the cut. This however involves a shift in the way the marketplace, jewellers and vendors view and think about coloured gems, from the mindset that bigger and heavier is better to one that instead sees and appreciates the beauty and elegance of a finely cut gem.
Let me give you a couple of examples. One of the things I provide to the jewellery trade and the general public is a gem recutting service. The following picture shows two gems that I recut for different clients, the first being a green sapphire, the second is a tanzanite. For each stone I took before and after pictures.
Now, after looking at the picture it should be fairly obvious that a precision cut gem makes the more appealing choice. Yes, the precision cut version of each gem is lighter but geez, they look so much nicer and for jewellers that makes them easier to sell and the price-per-carat of the newly cut gem is significantly higher then it was originally. Just pause and consider for a moment which one you would like to have in your ring and look at each day.
The next example illustrates very clearly the differences between profiles of a commercial cut gemstone and once it has been recut. The recut Ceylon blue sapphire is overlaid against it's original profile shown in pink.
Inspecting a Gemstone
If you are going to spend a lot of money on a gemstone make sure to have a good look at it first. The jeweller or shop assistant should have a special magnifying glass called an eye loupe available. Don't be afraid to ask if you can use it to better inspect the gem. Loupes can take a little practice to get the hang of so don't worry about appearing silly if you don't know how to use one. Ask the assistant to show you the correct way to hold it and to focus the gem. The gem should be held in a pair of tweezers or a gem grip. Ask the vendor if the gem has any inclusions and try to spot them yourself.
Take your time and inspect the facets, make sure they are evenly polished with no scratches and look for any chipping. Commercial cut gems are often only polished to a standard that precision cutters would consider a pre-polish. Check that the meetpoints are good. Does the cutting look sloppy or is it nice and crisp? What about that girdle, is it even and consistent all the way around or is it up and down all over the place? If the girdle is as thin as a razor blade than expect problems down the road as there is little structural strength and it is very likely to chip. Is the girdle even polished? A surprising number of cutting factories don’t even polish the girdle… this is just plain lazy. What about windows and fish-eyes?
Just as you would inspect a new car that you are thinking of buying for any marks, scratches, dents and defects, so too should you inspect a gem.
Lighting
You need a good light source to properly inspect a gem. You are looking at a very small object so the jeweller or vendor should have a lamp or suitable light source close at hand. Use it.
Another thing about inspecting a gemstone... those overhead halogen lights they have in the shops will make anything dazzle and sparkle like crazy, even a lump of coal. Try to view the stone in natural lighting if possible. If you can view the stone outdoors, position yourself so the sun is behind you shining over your shoulder when you look at the gem. This lets the light fall into the gem and bounce back to your eye.
Gems can sometimes look a little different under various lighting conditions. Artificial lighting, fluorescent and incandescant lights can make certain stones appear dull and flat or even slightly alter the colour. Try to view the gemstone in a range of different lighting, including good old daylight. Some gems really shine at night and look magnificent, aquamarines and blue topaz are good ones for this... they love the nightlights.
Windows and Fish-Eyes
So, what happens when a gem has been cut with incorrect angles that are too low or shallow? You get what's called a window or fish-eye right in the centre of your gem. This is probably the single most obvious thing that you will detect almost straight away when looking at a gem. There is a direct correspondence with the size of the window to the pavilion angles : the bigger the window the shallower the angles.
Generally you want to avoid windows in gems as much as possible. If you are spending good money on, for example, an expensive sapphire you want that it is full of colour and light and not with a hole in the middle that you can see straight through. Windows are usually considered a negative when assessing a gemstone and all things being equal should reduce the price on a gem to some degree. Windows reduce the amount of light, colour and brilliance that the gem displays back to the eye. You get a sort of donut effect with all the action around the outsize, nothing in the middle.
There are vendors and jewellers in the marketplace that will try to gloss over the fact that a window is evident in the gem (that’s if you bring it to their attention as they certainly won’t bring it to yours) they are trying to sell you, saying that it doesn't matter, that you won't see it once it’s set, whatever. To me it's like buying a painting with a hole cut in the middle and the salesperson saying, "oh it doesn't matter, you won't notice it once it's framed and hung."
Here is a simple test to see whether you've got a window in your gem. Take the gem and place it over some writing, like a newspaper. Now, looking directly through the table (top) of the stone do you see the writing? You'll know straight away if you've got a window or not.
The following illustration on the left is a commercially cut round smoky quartz being held over some text. Note the window through which the text is easily seen. It's pretty obvious isn't it. For comparison, the gem on the right is a correctly cut topaz. Can you see the difference?
Windows impact the colour, brilliance, fire and scintillation of a gem and can result in a gemstone that looks lifeless, flat and dull. Compare that smokey quartz above with the precision cut topaz... chalk and cheese. The topaz has been cut to correct angles and everything goes right into the centre as it should.
One last thing on windows - pretty much any stone, commercial or precision cut will, when tilted or viewed at an angle, exhibit some degree of windowing through the side of the pavilion. This is normal and for the most part unavoidable. What we are concerned with when we are talking about windows is what we see when viewing the gem perpendicularly, directly straight down, through the top of the table.
Goldfish Belly
A particular characteristic of commercially cut stones is what I like to call the goldfish belly. Basically all the weight is concentrated underneath the girdle in the pavilion giving the gem a look that's bulbous and out of proportion. The angles curving down the pavilion are too steep and as they near the bottom kick in under to the culet where they are too shallow, resulting in a window. When a gem has this sort of bulbous pavilion it's a sure bet that the crown is almost as flat as a pool table. This further dulls the gem as a well proportioned crown is critical to maximising the colour and dispersion (ie. think sparkles and fireworks). On the flip side, these gems can be good for recutting providing you don’t mind the reduction in carat weight. Recutting gems often comes down to an economic equation and whether you are prepared to accept a smaller weight.
Clarity, Flaws and Inclusions
In the diamond world, much is made of clarity. We are familiar with terms IF (Internally Flawless), VSI1 (Very Slightly Included 1), I (Included), etc. There is a well defined and established grading system. However, where diamonds tend to be relatively small, coloured gems are usually a lot bigger which means the chances of some sort of inclusion greatly increases.
In the world of coloured gemstones we still pay a lot of attention to a gem's clarity however the grading system is not particular well defined and tends to be quite subjective. Normally you want to find a gem as clean as possible. Eye clean is a term I use to describe a gem that, to the unaided eye, is clear of inclusions. That is not to say it is flawless, just that to the eye under normal conditions, the gem appears clean. There might well be some very tiny inclusions that are present but they do not impact the beauty of the gem.
Look for any flaws or inclusions that might be present in the stone, this is where an eye loupe is handy. Often stones can have internal flaws that are not easily visible at a quick glance. Its only later when you are at home and having a good close look at your purchase that you realise there's a crack or large veil in the stone that you didn't see when in the shop. Avoid the disappointment and really check that stone out first.
With the gemstones that I cut, I try my best to identify and describe any flaws or inclusions that might be present in the stone and give an indication as to how significant they are. Sometimes they are very very minor and barely noticable, other times they might be more so. Generally I try to cut my gems as clear, clean and flawless as possible.
However, not all inclusions are detrimental or flaws. Often there are natural inclusions such as "needles" in a gemstone. These needles are formed from different minerals like rutile or tourmaline. Rather then being a negative, people often look for these as a sign of a genuine stone and not an imitation. They also add something interesting to the stone and are very often quite beautiful in their own right. There are gem and mineral collectors who go nuts over inclusions in gems and actively seek them out. Demantoid garnets with their horsetail inclusions are one such gem and good specimens of these can go for big dollars.
Emeralds are a particular case. It is almost impossible to find an emerald that is completely clean. It is totally accepted in the industry for emeralds to have inclusions, indeed, if it didn't have inclusions then it would be highly suspect and probably a fake. These emerald inclusions even have a name and are called the jardin, a French term for garden.
Rubies are another stone that often has inclusions. Flawless rubies are scarce and incredibly expensive. Sapphires on the other hand you can quite reasonably expect to find very clean. So depending on the stone, the type and quantity of inclusions, how visible they are and so forth, all these things need to be considered. However, just because a gem has an inclusion doesn't mean it should be dismissed out of hand. No! It's just one factor of many that needs to be taken into account.
Meetpoints
Meetpoints are simply the points where facets meet or intersect. In a well cut gemstone, these meetpoints are as precise and accurate as possible. In the average commercial cut gem the meet points tend to be a bit more loose. Good meetpoints are a pretty fair indication as to the level of care and attention that went into cutting the gem. It's also a measure of the skill of the gemcutter.
However even with a precision cut gem it is unlikely that every single meetpoint on a gem is going to be perfect. Such a high level of perfection is usually only reserved for competition gemcutters where it is not unheard of for an individual to spend forty or fifty hours on a single gem. It would be nice to have that luxury of time but for gemcutters like myself we have to make a living and so try to keep the hours down to a more manageable level. Four to six hours should cover most average sized gem. Gemcutting is always about compromises.
Colour
Colour is a science in and of itself and plays a key role in determining the value of a gemstone. The three main terms are :
HUE : The actual "colour", eg. red, blue, green.
SATURATION : The richness or vividness of the hue.
TONE : The lightness or darkness of the hue.
At the risk of oversimplifying a complex subject - trust your eye. Be wary of gemstones that are so dark you cannot see through them and appear to swallow the light. Garnets and sapphires are a common one for this.
Clients will regularly ask me for a gem where the colour must be a pure hue, for example, it must be a pure blue sapphire or a pure red garnet. Nature seldom works like that. Finding a gem with a pure single hue is a very rare thing indeed and the price can skyrocket accordingly. I could look at and cut a hundred pieces of rough and not one of them will be a pure hue. The vast majority of gems will have some degree of secondary hue. For example sapphires will often be blue with a hint of a green, or red garnets with a touch of orange. It's just how these stones are. Having secondary hues is in no way whatsoever a bad thing as this can add wonderfully subtle levels of complexity, beauty and depth to the gem. People have to remember that everyone always wants pure hued perfect gemstones and they are always the first ones to sell and the hardest to replace.
Then there are pleochroic stones which is a technical term for many colours. Some stones are dichroic showing two colours, some are trichroic showing three colours. When you move the stone around and view it from different angles you see different colours. Tourmalines and tanzanites are good examples of this. This characteristic should not be viewed as a negative thing. It's what makes each gem a beautiful and unique creation.
For the precision gemcutter, one particular factor that takes some experience is knowing how to orientate a rough stone correctly to get the “best” colour. This is something that certain stones like Australian sapphires are very sensitive to and where Australian gemcutters have a home field advantage. Rarely does the best colour and the best yield coincide and the gemcutter needs to use their judgement and skill to find the most optimal orientation to get the best stone they can. This usually involves a compromise so that if I want the better colour I may have to accept a smaller or differently shaped gem than what I could otherwise obtain if I went for a heavier gemstone.
This is where commercial cutting factories usually come undone with Australian sapphires. In their pursuit of maximum yield they don’t realise that it is crucial to orientate the rough stone correctly to make the finished gem look nice and bright. They are more used to Ceylon sapphires which are much more forgiving with orientation and have quite a different lighter blue hue to begin with. With Ceylon sapphires they can certainly chase the yield but do that with Australian sapphires and the resulting gems will almost always come back dark and dull.
Australian Black and Parti Colour Sapphires
I should mention one particularly fascinating and beautiful type of colouration that occurs which I am very fond of and that is the parti-colour which is found in Australian sapphires. Parti sapphires are just awesome and each and every one is totally unique. These gems show a combination of two or three colours, usually blue, green and yellow. Have a look at my sapphire page for examples of parti colours. These are highly desired for their unique combinations of colours.
While we're discussing sapphires, I'd like to quickly mention black sapphires. Look, I'm not going to beat around the bush, I'm a big fan of Australian sapphires, always have, always will be. I think these stones are the fine Scotch whiskeys of the gem world, with a depth of colour, complexity and rareness that has it's counterpart in the very best of single malts. However, if Australian sapphires have an Achilles' heel it is that they can often be darkly saturated almost to the point of appearing black due to the concentration of iron and minerals in the ground during their formation. These are usually very darkly blue hued stones and may be referred to as midnight blues. This is all perfectly fine, each stone is what it is.
Why I mention this is that a good black sapphire should still be gem quality! Even though it is dark to the point of appearing black, it should still be gemmy and transparent, as free of inclusions as any other gem one might buy. If you hold the gem over a small torch or up to a lamp you should still be able to see through it. If you cannot, if the sapphire is opaque, then what you are purchasing is a low grade sapphire, something that we call corundum and this affects it's value accordingly. A high quality black sapphire is not that easy to come across, a low grade corundum one is. Corundum is the family name of sapphire. When red corundum is gem quality it is called ruby. All other gem quality corundum is called sapphire. Anything that is not gem quality is just corundum.
An exception to this is with star sapphires which are usually cut as cabochons. By their very nature, star sapphires need to be opaque (or semi-opaque) in a particular way for the star to occur. A really good star sapphire is actually quite scarce and really cool to see. The best way to see the star is with a single light source, like a torch or the sun. The star will appear with six-rays and how well it is centred on the cabochon, it’s crispness and brightness will influence it’s price accordingly. Australian star sapphires are often golden in colour and make great ring stones. Keep an eye out for these beauties.
What I have said regarding black sapphires needing to still be gem quality applies to other black gemstones, such as garnets which can often be quite dark. There are vendors that will sell low grade material at high prices because they can. They rely on people not knowing any better. There is absolutely nothing inferior about good quality black gems, they have their place and there are people that specifically want them. All I can suggest is that if you are about to buy one, put a torch under it and make sure it's gemmy. One exception (there are so many exceptions with gems, aren’t there) is the black spinel which is totally opaque and takes an incredibly glossy polish and makes a superb black gemstone. Black sapphires and black spinels are my choices if you are looking for a beautiful black gem.
Special Colour Terms
What do I mean by this? Well in the marketplace you will quickly come across special colour terms such as cornflower blue sapphire, siberian amethyst, padparadscha sapphires, pigeon blood red ruby or paraiba tourmaline and the like. These special terms refer to very particular instances of a colour or a gem coming from a very specific origin. Gems genuinely deserving of these designations usually demand a premium and because of that some vendors are quite loose with the truth when describing the gems they have for sale as being such. I've lost count of the number of times I've seen a siberian amethyst for sale which just wasn't one. In the case of siberian amethyst, it doesn't mean it comes from Siberia, it refers to a very specific type of red flash or colour that appears in certain high quality amethyst. I can't remember the last time I saw a piece of amethyst that could honestly be called siberian. It's very rare and seriously hard to find and comes at a price. But a quick scan of ebay or other online marketplaces would lead you to a different conclusion.
What I would advise is that if you are really after one of these gems that has a special designation, do your homework first. Find out just what that term refers to and look at examples if possible. It is important to see these gems in the hand as photos rarely do justice to the colours. Sometimes the gem may have a certificate which will have on it the designation, some gem labs will do this, others will not. And keep in mind that some certificates are not worth the paper they are printed on so ensure the cert comes from a reputable gem lab.
And as always, make sure the vendor has a money back refund policy to avoid disappointment. If you are looking for those special colours you need to see the gem in the hand and not rely solely on pictures.
Colour Change vs Colour Shift
The colour in some stones can shift or actually change depending on the type of light it is being viewed under. One of the most well known stones that changes it's colour is alexandrite. In daylight and under fluorescent lights it can exhibit a strong teal blue colour. View the same stone under incandescent, halogen or even fire or candle light and you'll see a strong purplish red hue. Colour changing gems are rare and expensive. The more marked the colour change is the more the price goes up. Good alexandrites can blow your mind both with their colour changing beauty and the prices attached to them. This is one of those gems that if you have to ask the price you probably can’t afford it.
Colour shifting gems are also quite fascinating however the change is not as marked. These are gems where the colour shifts from one colour to a neighbouring hue, like from pink to peach, or yellow to orange. Colour shifts tend to be more subtle. Some garnets exhibit colour shifting, so can sapphires and tourmalines.
In my opinion, colour change is where the colour changes quite dramatically, often to it's inverse or near inverse, for example blue to red. Colour shift is where the colour change is much more subtle and not as pronounced. In the marketplace, the term colour change is what tends to hold the prestige as opposed to colour shift. It is a subjective thing and some vendors can be quite, ah, imaginative when applying the term colour change to a gem they are selling. Exercise caution when buying a gem described as colour change. Colour change is not considered a negative and people actively seek them out.
Synthetics and Imitations
Within the marketplace one must be very aware that synthetic and imitation gemstones exist and do so in great quantities and unfortunately the potential to be defrauded is there. Always buy your gemstones from a reputable vendor or jeweller.
With many of these imitations it can be exceedingly difficult to tell them apart from the genuine item as they are made to imitate the very finest of their target stone. Even professional gem labs can have difficulty in identifying a fake. Synthetic diamonds are going to cause a lot of grief out there, you can be sure of that. Remember the caveat : BUYER BEWARE!
Imitations have been around for along time. In 1888, French chemist A.V.Verneuil succeeded in synthesizing rubies. In 1910 synthetic sapphires appeared. Today many people have heard of YAG and CZ (cubic zirconia is not to be confused with Zircon which is a completely natural and desirable gem). There is nothing wrong with synthetics and imitations per’se so long as they are designated and sold as such. They do have their role in the market. Vitually every natural gemstone has it's imitations : diamonds, sapphires, rubies, emeralds, amethysts, citrines, pearls and opals, just to name a few.
Treatments and Enhancements
Gemstone treatment is a very common occurrence and is one of those things that invokes a lot of debate in the industry. In short, gemstone treatment is done to improve the quality and marketability of the final gem.
The treating of gemstones to improve their colour is as old as the custom of wearing stones itself. It probably first started when someone accidently dropped a stone into a fire and upon retrieving it found that it had altered the colour. Using fire in this manner is the traditional way to treat many stones but has been superceded in large part by controlled heating in special ovens or even simple pottery kilns. This method has wide acceptance in the industry.
The types of treatments are many and varied, some are looked upon favourably and others not so much. Some treatments are done ubiquitously to certain gemstones to improve colour and remove or mask impurities and flaws thus dramatically altering its appearance and the value. Heating, oiling (emeralds in particular to fill the cracks), irradiation, lasering, dyeing, acid, berrilium are common forms of treatment.
For certain varieties of stone in the marketplace, particularly the more expensive one like sapphires, rubies and emeralds, treatment is the norm. A lot of debate centres around disclosure to the buying public of any treatments done to the stone as well as the distinctions between "treatments" and "enhancements". Industry and governmental guidelines can be unclear and in some cases completely lacking. Treating stones is relatively cheap and is done on a large scale, turning often inferior stones into something more marketable. This all impacts on a gemstone's value and the industry at large.
Generally speaking, an untreated stone of fine quality should demand a higher price and premium when compared to a similar stone that was subjected to some manner of treatment. Fine untreated stones of any variety are getting scarcer by the day and harder to come by.
Heating
Now, reading the previous section you might think that all treatments are a bad and terrible thing. Not so!
Heating is probably the most common method of treatment performed. Do I have a problem with it? Short answer is no, not at all. Simple heating is pretty much what it sounds and with sapphires in particular is done to put the finishing touch on what nature has produced. I'm not an expert on it but from my understanding the sapphires are placed in a kiln/oven and heated to the lowest possible temperature for a certain period of time to achieve the desired effect which is to remove or dissolve any silky rutile mineral inclusions (known as silk) back into the matrix of the stone. This has the effect of improving the brightness, clarity and colour of the sapphire. It doesn't damage the sapphire, weaken it, or lessen it in any way. Heating has been done since the dawn of time and still is being done in places using quite primitive techniques... a person sits next to a charcoal burner with some rough sapphires on it and they blow through pipes to heat the charcoals and induce the changes in the sapphire.
Remember that sapphires are formed way down under the earth's crust where it is pretty damn hot and in the case of the Australian sapphires were brought to the surface via volcanic action which is pretty damn hot as well I'd imagine. It's a bit like baking a cake -. most sapphires are perfectly baked, others were pulled out of the oven a bit too soon or perhaps cooled a bit too quickly. All heating does is put the sapphire (cake) back in the oven for another five minutes to finish it off. It's just a small extension of the natural processes that the sapphire has already undergone.
The effect of silk in a sapphire is sort of akin to putting cotton wool in your ear. The cotton wool muffles the sounds - you can still hear but the words are not distinct and clear. Remove the cotton wool and suddenly you can hear clearly. Silk has a similar effect on light within a sapphire, it muffles the light and brilliance often giving the gem a sleepy appearance. Remove that silk and the sapphire appears to have more brightness and life. The amount of silk removed by heating can vary between stones to a greater or lesser degree.
As far as I’m concerned you’d be silly to dismiss sapphires just because they have been heated. Beware of vendors or folks in forums that tell you a sapphire must be totally natural and unheated or it is no good. That’s just rubbish talk.
Pricing
If ever there was a rabbit hole to go down it's that of gem pricing. Nothing will do your head in more than trying to figure out why pricing for gems seem to vary so wildly across the marketplace both physical and online. Give the same gem to a dozen different sellers and you will get a dozen different prices, high and low.
The gem trade is an unregulated marketplace with perhaps the possible exception of diamonds but even there they are highly controlled by the big players (think DeBeers) and prices are tightly managed as is supply. One should keep in mind that diamonds are not as rare as you might think or as the slick marketing portrays, after all they drive a global multi-billion dollar industry with many many players and companies involved all wanting their slice of the pie. Diamonds are everywhere in every jewellery store in every town and city around the world. The fancy diamonds, like the pinks, yes they are certainly rare but your average white diamond not so much. They've just been very well marketed. The natural diamond industry is in a big existential fight at the moment with the rise of better and better quality manmade diamonds which are becoming cheaper and driving down the prices for the natural ones. There is a lot of discussion out there about diamond pricing should you want to know more.
With coloured gemstones prices are unregulated and sellers can and do put whatever price on them they choose as is their prerogative. It is impossible to try and figure out what factors and considerations go into how someone determines their pricing. That person or company might have their own sapphire mine or was in the right place at the right time to score a big bag of rough stones at a bargain price. Perhaps they inherited the rough. Or like many gemcutters, myself included, they have to buy the rough stones off rough dealers and generally have to pay top dollar for it. Who knows. The demand for quality gem rough is very strong, everyone in the industry is after it.
Cutting costs: did the person cut the gems themselves or was it sent overseas to get cut in a factory for relatively next to nothing. For someone like myself it takes time to sit down and cut high quality gems plus don't forget that it takes years of practice to develop the necessary skills. One doesn't just sit down one day without ever touching a faceting machine and decide to cut a $10000 sapphire. What's that time and skill worth? Same goes for the handmade manufacturing jeweller versus the big mass-producing chainstores.
All I can suggest is just look around and do your due diligence and research. Get a feel for what is out there and what the prices are for the sort of gem you are specifically looking for. Check out your facebook, etsy and ebay sellers, visit some jewellers and big brands (btw, the markups that the likes of Tiffany, Bulgari and others put on gems is staggeringly eye-watering!), talk to some gemcutters and see what they have and so on. You'll get an idea after a while whether someone's prices seem fair and reasonable or whether they are just trying it on.
I believe that pricing needs to be fair to both the buyer and the seller. I arrive at my pricing with much thought and consideration as I am sure others do too. If you want cheap there is plenty of cheap out there. If you want quality, that's a different story.
One very important thing to remember is this: anyone who has a good gem is not going to sell it cheap. If a gem is cheap there is usually a reason for it. Perhaps the gem itself might be not quite what you think it is or what the seller wants you to believe (might even be fake) or perhaps they are just in a hurry to sell it for some legitimate reason. As a rule good gems aren't cheap, but then you can come across a genuine bargain sometimes.
Certificates and Trust
At the end of the day you want to be sure that you are buying exactly what you think you are buying. You don't want to discover later down the track that you purchased a fake or that the gem you were told was untreated has indeed been treated.
Buy your gem from a trusted source, be it from a bricks-and-mortar shop or over the internet. If you are buying over the internet make sure that the vendor offers a money back return policy so that you have a chance to inspect the gem in the hand. If they don't then you don't want to buy from them. It's surprising how different a gem will look in the hand compared to the picture of it on the vendors website or ebay page.
If you are intending to drop some serious cash on a beautiful gem, make sure that it comes with some sort of certificate from a reputable gem lab and explicitly notes whether it has been treated or not. You may have to pay a little extra for the certificate but it's worth it and comes in handy when trying to insure the gem or sell it later on.
If knowing whether the gem has been treated is important to you (and for many people it doesn't really bother them), specifically ask the vendor the question, "Has this gem been treated in any way?". If they skirt around the question or reply something along the lines of "it’s natural", then that is not good enough. Yes, you can see that the stone is indeed natural and not a fake but what you are specifically asking is whether it has been treated. It's two different things. Natural does not mean it’s untreated.
Sometimes the vendor or shop assistant might genuinely not know whether the gem has been treated and simply answer that it hasn't, that it is natural. In this case err on the side of caution and assume that it has until proven otherwise. A certificate from a gem lab is usually the best way to go. Otherwise feel free to take their word for it. Again, it might not really matter to you one way or the other. There is absolutely nothing wrong with a heated sapphire or oil-filled emerald, they are things of beauty, as long as you know that is what you are buying.
Finally
When trying to choose a gem, something to keep in mind is that the most expensive gem in front you might not be the right gem for you. For some reason you can’t quite put your finger on you find yourself drawn to a different stone because there is just something about it that is calling to you. It might not be the biggest or the best cut or even the original shape you were wanting, perhaps it’s the colour or the way it catches the light. It could be anything. Trust your eye and your first impressions, they are often the best judge of such things. Remember, you are meeting these gems for the first time and just like people you can gravitate towards some and away from others without really knowing why.
Sometimes when a client can't make up their mind between gems (and it always boils down to two every time), I tell them to take a few days, there’s no rush and you'll find it's usually the gem that you see in your mind's eye first when you think about them, the one that keeps popping into your thoughts throughout the day or watching the TV at night. You'll know which one it is.
Happy gem hunting!