I do periodically write about this issue as I am not convinced that – even though the practice has been around for a while – it is yet common knowledge. In short, glass filling is the practice of fracture-filling rubies with lead glass to improve their appearance. I’m going to lay it on the line, folks: this is bad. It takes poor quality, fractured material and turns it into pretty looking transparent red. It looks good but it is complete junk. Worse than that, it is no longer a ruby.
What is the treatment?
Fracture-filling is not new; emeralds have been fracture-filled with oil for years, and it is a completely accepted treatment. The idea being that you find a filler with the same or similar refractive index as the stone and the appearance of fractures are minimised. With emeralds this is fine, as oil is used, which can be removed if necessary and the stones re-oiled; in addition, the original material is usually reasonable. With rubies, the practice of lead glass filling takes rough that is opaque or near opaque – material that would otherwise be unsaleable – and permanently filling it with lead glass. Poor quality corundum is soaked in acid to remove mineral inclusions leaving a weakened and brittle stone; a stone so weak in fact that you could crumble it to powder with your hands. These skeletons are then infused with lead glass, which makes the stone stronger and prettier. The results are actually extraordinary: opaque corundum can be turned into stones with high transparency. So what’s the problem?
The Problems with Glass Filling
There are three main problems: firstly it is an extremely unstable treatment, secondly – and rather crucially – once a ruby has been glass filled it is no longer a ruby and thirdly, it is frequently not disclosed. Let’s take these one by one:
The GIA reports describe glass filled rubies like this: ‘ A manufactured product consisting of lead glass and ruby…unstable to high temperatures and to chemical agents.’ This says it all. The treatment is extremely unstable. Heat during jewelry making or repair will ruin it. Pickle to remove fire-scale will ruin it. Even the wearer can ruin it – most household cleaners will ruin it. Lemon juice will ruin it.
The stones are not rubies. They are ruby and glass composites and in many cases will be more glass than ruby.
The treatment is not disclosed. Sometimes this is blatant fraud; sellers will blatantly charge ruby price for something that is effectively worthless. I have suppliers who say they are finding glass filled rough in with the decent stuff. But most of the time it’s happening because people simply don’t know. They go to a show and buy a ruby and think, ‘oh I got a great deal’ and then sell the stone in jewellery as ruby. Sometimes even the big stores are selling these items undisclosed and, since I’m sure these stores don’t want to wreck their reputations, it must be that they simply don’t know what they are selling. From my own experience, I myself have found at gem fairs that when I’ve asked, ‘is this glass filled?’ that sellers have readily told me. But I have not been convinced that they would have done so, had I not asked.
This is really important, because the retailer is completely liable, whether the mistake is deliberate or accidental, they can be sued for not disclosing this treatment.
How is it detected?
Well, the good news is that unlike other nefarious treatments, this one is really easy to spot under magnification. A microscope or even a loupe will show up low relief fractures, gas bubbles (as is really common with glass), voids, and a yellow and blue flash effect. Failing this, one of the easiest ways – in my experience from attending gem fairs – is simply looking at the price: if it looks too good to be true, it probably is. That is, if you are looking at near-transparent ruby for a few dollars a carat, it’s probably glass-filled. This is fine if you’re buying at this stage – the danger comes if someone thinks they’ve got a great deal, and sell the stone on as ruby.
What’s the take-home message?
I’m not pulling punches with this because it really is complete rubbish. If you buy it and sell it on you are liable. There are also reports that it is being seen in sapphire as well as ruby, although the ruby composites are completely ubiquitous. Always, always ask, if you are buying a ruby. First question: ‘is it glass filled?’ In my experience, you will be told. Carry a loupe and learn how to use it. It’s not even always deliberate fraud; sometimes the sellers themselves don’t know what they’ve got on their hands. And remember, forewarned is forearmed.
What a lovely sounding title. If there is one thing that people generally want to avoid in gemstones, it’s a fracture or a feather; whether the crack is surface reaching or completely included in the stone, there’s always the danger of it opening up and splitting or at least weakening the stone. More than that, it’s unlikely that it’s ever going to actively add to a stone’s beauty. However, it’s such a common feature of stones, and indeed sometimes an integral part of the stone’s make-up that it bears closer inspection. A fracture can tell you how the stone was formed, give you information about whether and how it’s been treated
The first thing to be said is that all fractures are not equal. There is a difference between a large, unsightly feather right under the table of a diamond and a delicate fingerprint pattern inside a ruby. In addition, some types of stone are much more likely than others to be fractured in the first place. Let’s find out where they come from and in what forms you might find them.
Where do they come from?
During crystal growth; a result of internal tensions caused by structural defects or tectonic activity
During crystal growth; an integral part of the stone’s make up – eg parting in labradorite, cleavage etc
Whilst formed crystals are in the host rock, due to changes of pressure or mechanical damage produced by tectonic activity.
Secondary deposits, when gems are transported and accumulated, eg after being tumbled and washed down a stream.
In primary deposits, during mining or the recovery process (blasting and crushing of the rock).
During cutting itself: sawing, cutting and polishing, accidental blows or if internal tensions release, or if the stone becomes too hot.
In some treatments, due to thermal shock
During heating, included crystals inside the host crystal can expand leading to ‘halo fractures’
For mechanical reasons during jewelry making or repair process, eg setting
Once in jewellery, normal wear and tear, for example accidental bumps and abrasions
Large fractures in stone varieties known for easy cleavage; tanzanite, kyanite or topaz for example should be avoided. They don’t look good and worse, will seriously impact the durability of the stone. Any blow or accidental damage could cause the fracture to open up. As stone-cutter Meg Berry states, she likes to apply the ‘rule of thumb’ when it comes to fractures in stones; namely, if you can snap it with your thumb, you probably ought to. Smaller fractures are a different matter; some milky aquamarine is full of fractures and beautiful, watermelon tourmaline tends to come up quite fractured and of course with emerald it’s almost impossible to avoid. Below, the aquamarine is crazed with tiny fractures, but it adds to the density of the colour and the movement of the cut. The tourmaline slice is imperfect but the colours are still bright and the emerald looks like a planet, with its visible fractures and liquid inclusions.
It’s hard to think of any situation where a large inclusion adds to the beauty of a stone but as I was writing this I thought, if there’s one thing I’ve learned in 10 years in this business and that is that people are endlessly creative and can conjure beauty from the most unprepossessing of raw materials. Enter Jamie Johnson, and her Golden Joinery collection. These are all one of a kind; broken stones set in sterling silver with the seams of both cracked halves dipped in 22k gold. They are absolutely stunning. Below from left Aussie Boulder Opal Joinery Ring, $2860, Golden Joinery Turquoise Earrings, $2330 (photos courtesy of New Twist), Pendant necklace in oxidized sterling silver with 22k gold and rainbow moonstone, $2,970 and finally the group at the bottom featuring turquoise, ruby, boulder opal and green tourmaline (photos courtesy of David Wentworth at Flutter Studios). Aren’t these amazing?
Ah yes, labradorite. Think of labradorite and in your mind’s eye you’ll no doubt think of a multi-veined stone with the characteristic flash. Years ago I was having trouble with customers sending back stones because not only is the stone soft, but there’s a thing called lamellar twinning. Also known as ‘repeated’ or ‘multiple’ twinning, this results in the layered make up of the stone, which makes it prone to fracturing along these twin planes. It is also, however this make-up which gives rise to the flash – it is the light refracting off these planes that results in the characteristic labradorescence. So when customers tell me they want great flash and no fractures, I kind of want to throw my hands in the air and shriek!! However, I have now done my best with it; not entirely fracture-free but my labradorite is less fractured than most. I try to buy the translucent material with the superior flash, and that way I have happier customers and fewer returns. Even so, you’ll see in the picture below that there are still fracture lines across the stones. It’s pretty much unavoidable.
Cleavage is the tendancy of a crystal to break along distinct planes, and some stones are more prone than others, depending on their specific characteristics. It’s where the atomic bonds are weaker, so the crystal can split easily along those lines. Some have no cleavage – eg quartz, opal, agate, turquoise, ruby and sapphire, and some have perfect cleavage along one or more planes, for example topaz, diamond, kyanite, and all feldspars. It’s more of an issue during cutting – and in fact it used to be used to divide large gem crystals. Now cutters make sure that they cut such stones to minimise the chance of the stone cleaving during setting.
So we have seen that fractures have a function and a place. They may even be beautiful, and certainly they are sometimes unavoidable. I think I ‘ve gone on enough so next time we will be looking at other kinds of fracture – eg halos and fingerprints and also clarity types: the tendancy of some stones to be more included than others.
Aquamarine is a really great choice of stone; it’s pretty gemmy without being insanely expensive, it cuts well and takes a really high polish. In its transparent form, it’s more pricey but I just love the milky variety; in lovely shades of pale blue to sea-green, it is misty, hazy and dreamy. It’s common to find this material full of fractures and veils, but when it comes clean with a lovely translucency it is a beautiful, glowing stone. It is named after seawater itself: aqua = water and marina = of the sea and it is in fact a form of beryl, the same mineral as emerald. Unlike emerald, it grows in large and frequently clean crystals so it’s relatively easy to find it in large sizes and in fact can be exceptionally clean. Top colour is a moderately strong blue to greenish-blue. It’s a great jewellery stone and versatile as it’s also exceptionally hard – so a good option for a ring stone. The gemstone for March, aquamarine is offer protection in battle and make the wearer unconquerable; what more could you want! Clockwise from left below: CJ Bijoux aquamarine and 18k gold ring, AF Thomas aquamarine, blue topaz and 18k white gold ring, Gemory Design aquamarine and sterling silver ring and Gems Berry aquamarine and sterling silver ring
We sell a variety of really gorgeous, translucent aquamarine in cabochons and rose cuts as well as rose cut freeforms. To check them out, click here
Many years ago, shortly after I started out, the price of prehnite went shooting up. It was one of those odd things, where I had to do a bit of a double take. What could be going on? I was told, it was because it was being used as a jade substitute for the Chinese market. I did another double take, because I just couldn’t see it. Prehnite is so commonly pale, fractured, full of wisps and veils that I just couldn’t see how it could possibly substitute for jade. And then they brought out the good stuff; deep green, clean and glowing with an unearthly, dreamlike lustre. Ever since, I’ve tried to stock the better stuff, because when prehnite is good, it’s very, very good indeed. You might never even have heard of it. The GIA thinks not, as they have included it in their ‘Hot Gemstones’ round-up, but that makes it an excellent choice as you are not likely to run into it in your local jewellers. It’s a bit different, unusual and the prices (except for the really fine stuff) are pretty sensible. For meaning, it is best known as the stone of unconditional love, said to connect the head to the heart. It’s found mainly in Australia, Canada, China and the USA, and it’s a good choice for anyone who likes their stones untreated as it never is.
I’ve decided to do a series of posts on inclusions, as it is simply one of the most frequent topics that comes up with customers. Everyone knows the value of a nice, clean gemstone: no-one wants a diamond with a dirty great fracture, or a ruby with a big black crystal under the table. However, the search for a perfectly clean stone is a bit of a fool’s errand. The GIA no longer uses the term ‘internally flawless’ to describe diamonds as there is simply no such thing; with increasingly powerful microscopes, if you magnify anything enough times, you will find something. But above all, I think we need to reconsider attitudes to inclusions. The GIA doesn’t call them inclusions; preferring the term ‘clarity characteristics’, and if you believe that the very words we use are instrumental in influencing how people feel about a thing then we can see that this is a much less judgemental term to use. They describe clarity characteristics in a stone as ‘the eyewitnesses to its birth’. They can provide valuable information as to how and where it grew, indicate events in its history and sometimes on a broader scale, in the the events and internal turmoil of earth’s history. They can help detect whether a stone is natural or synthetic and provide evidence as to whether the stone has been treated or not. They almost always tell a story. And if you’ve ever held a pile of synthetic rubies in your hand you might find yourself thinking, as I have, that stones without inclusions can have all the appeal of a piece of coloured glass.
Golden Rutilated Quartz Cabochon Freesize, 41.975 carats, 29.8×21.5×9.6mm, $138.40
Golden Rutilated Quartz Cabochon Freesize, 9.65 carats, 16.1×12.1×7.2mm, $31.85
Inclusions are not always bad, either, and that’s my subject today. Sometimes they have a beneficial effect on a stone’s beauty, and that is certainly the case with needles! Needles are defined as long, thin, solid crystals or hollow tubes; if it’s hollow it might be filled with fluid or gas. A group of fine needles is called ‘silk’. Silk is what gives high quality sapphires their soft, velvety appearance, and can give rise to cat’s eyes and stars, if it is oriented along the stone’s crystal planes. Needles to me are at their best when they are present as visible needles in stones such as quartz and prehnite. These stones are desirable precisely because of their inclusions. In quartz, rutile needles can appear gold, copper, red and black. They can occur sparsely or in clumps; they can be thick and coarse, or they can be fine, the so-called angel-hair variety. You can also get rutilated prehnite; a soft, green bodycolour intersected with striking black needles. When we talk about inclusions it’s easy to see this as always having a negative connotation but it simply isn’t so. Rutilated stones really need only a simple, beautiful setting to show them off to their best, however, I love the setting below, where the design on the body of the ring echoes the spokes of the rutile in the quartz.
To shop our collection of rutilated stones, please click here. Next time I’ll be talking about the dreaded fractures!
When I first started selling gemstones 10 years ago (blimey) one of the first stones that I focussed on was London Blue. It was reasonably priced, plentiful and the colour was like no other. Before I started my journey into gems, blue topaz to me meant swiss blue; bright, vivid cornflower blue. I’m not really a bright and vivid kind of girl (!), or at least, the colours don’t look good on me, so it wasn’t a stone I was interested in selling. London Blue, however was a different story. Prussian blue, petrol blue, I had so many names for this distinctive and elegant shade of greenish blue. No other stone could touch it, except perhaps blue tourmaline (indicolite) but you needed deep pockets for that. And my customers appeared to agree! They couldn’t get enough so I started cutting it in all shapes and sizes. However, around 2015 something unpleasant started to happen; the price started jumping up, the quality began to waver. What could be happening? Well, there two main drivers of this price increase. First of all, let’s be clear. When we are talking about blue topaz we are talking about treated topaz. Blue topaz is irradiated white topaz. It has to be irradiated, and then it has to be cooled – that is, allowed to sit whilst the radiation disperses. The darker the topaz, the longer it has to sit. So whilst sky blue topaz has a 3-month cooling period, London Blue has something like 18 months. There are not many places that treat London Blue, and so that in itself puts a pinch on demand. Added to that you have the increasing popularity of the stone, the unwillingness of suppliers to treat more rough – since it effectively ties up millions of dollars for a year and a half with no return during that time. There is also a natural caution amongst suppliers around the popularity of London Blue. Is the increase just a blip, or is it here to stay? Because it’s one heck of an expensive gamble to treat more rough because it is popular now, only to find that in a year and a half it’s gone out of fashion and they have a whole lot of treated rough that they cannot shift. In my view this wont happen; I think the colour is unique and it has enduring appeal, but I’m not the one having to stump up the cash.
However, this is only half the story, and the woes of London Blue go further back, as so many things do, to the recession of 2008. What happened is very simple; topaz is sourced largely from Brazil, and during this time many mines were forced to close. They have never re-opened and now topaz supply is down by around 60% from pre-2008 levels. For a while there was enough rough in circulation to not have too much of an impact, but this corner was turned in around 2015, when demand began to seriously outstrip supply. So there is now a serious problem in that there are two major pinch-points in the supply chain; a lack of good quality untreated rough coming out of the mines resulting in an increase in price at this point. This has then led to suppliers taking a very conservative attitude towards treating the rough, not wanting to tie up increasing amounts of money in a stone that they fear may be something of a bubble. In reality this seems unlikely. Demand for the stone is still high; it is still a unique colour, and it still is available in clean quality. Although the colour has much more variation than it has in the past, with more greyer, less saturated material on the market some people prefer this, feeling that it looks more natural, more gemmy.
So in short, the outlook for London Blue is that prices aren’t coming down anytime soon. This makes it more expensive to buy, but it also means that it’s unlikely to be a wasted investment. And you could do worse than start here, from top, Ananda Khalsa’s London Blue Topaz ring is set in warm 22 carat gold and sterling silver and highlighted with sparkling diamond dots. I love blue topaz in silver, but putting it in gold takes it to a completely new dimension. I’ve always loved the solid, crafted simplicity of William White’s ring settings; in fact I have a number of stones in my collection I’d love him to set for me. The ring below is a 10mm cabochon in a satin-finished sterling silver band. I do like the angular lines of Eva Dorneys London Blue topaz rings in 9kt gold and sterling silver and I also love the cool stacking system of Barbara S Jewellery. That’s 2 rings, not one; an aquamarine and a London Blue
I do have new stocks of 6mm London Blue topaz cabochons; they are more expensive than I would like them to be but trust me when I say I have shaved the price as low as possible! You can find all of my London Blue here.
Watermelon tourmalines classically mimic the fruit, with their juicy fruit and rind; bright pink in the middle, green on the outside. However, they come in so many different colours, representing the full spectrum of tourmaline’s impressive colour range. In fact tourmaline’s original name was ‘turamali’ which means ‘mixed colours’. It’s quite simply one of my favourite stones, but maybe not the easiest to set; it’s not always easy to find pairs and the profiles are often very uneven and bockety.
Tourmaline grows in pegmatites – veins that run through rocks created by molten magma from volcanoes. As the magma cools, cracks form which fill with a solution of water and minerals such as iron, lithium or manganese. Over thousands of years, these turn into tourmaline crystals, and it is depending on which of these minerals is present that determines the colour. So how do you end up with more than one colour in the same stone? This happens when the trace elements change in concentration or composition during a crystal’s growth. This can result in a core of one colour and bands of different colours, or zones across the length of the crystal. A single tourmaline crystal can contain up to 15 different colours. Tourmaline is the birthstone for October and I always think that is so lucky, as you have such a huge choice of colours. It is said to be particularly beneficial to artists and those in creative fields.
Watermelon tourmaline lends itself wonderfully to carvings – in particular butterfly wings and leaves look great, but arguably the best way to display it is quite simply, in slices, to show off its saturated juiciness to full effect. Although it can be prong-set, I love to see these slices in bezels. I always think of India Mahon as the absolute queen of tourmaline, and I also especially love Sarah Walker’s classic settings below. I haven’t seen slices set like this very often and I really like it. Links and titles on each photo.
I have a range of quality watermelon tourmaline slices, to take a look, click here
Gem treatments have become ubiquitous in recent years. So many stones are treated, heated or fracture-filled; pearls are bleached, jade and turquoise is stabilised. It’s a thing that a some people react against, instinctively put off by the idea of it, as if it detracts from the stone. I’ve often encouraged people to not think of it like that; instead think more of how wood might be waxed or oiled, to bring out its natural beauty. Having said that, not all treatments are equal and we are now at the stage where the gem and jewellery industry has laid down clear guidelines and boundaries as to what is acceptable and what is not. For example, the industry accepts heat treatment of sapphire and ruby, to improve the colour. It accepts fracture filling of emerald, as emerald is such a brittle, fractured stone, whereby the oil filling helps to make the fractures less obvious. It accepts the stabilisation of turquoise whereby these soft stones are infused with wax or resin to make them harder, more durable and better able to take a polish. Certainly untreated stones will always attract a higher price than treated, but these treatments are accepted, as long as they are disclosed. However, there are many treatments that are considered much more controversial, for example the glass filling of rubies and bleaching and dyeing of jade. Anything, really, that results from the taking of very low quality rough and making it appear much, much better than it really is. BE treatment, or beryllium treatment of sapphire is one such treatment, and it has become so ubiquitous in coloured sapphire that many reputable dealers are simply not supplying coloured sapphire.
What is it?
Beryllium treatment is a form of lattice diffusion treatment. Such treatment, previously known as surface diffusion, or bulk diffusion involves the super-heating of pale, colourless, poorly coloured or even dark material in the presence of other elements. Titanium diffused sapphire has been around for a while, and in fact is rather easy to spot. It penetrates only the very surface of the stone and if you look at it under a microscope it is easy to see colour concentrations along facet edges. It’s a problem as it can easily be removed with repolishing. However in the early 2000s, many people began to become concerned at an influx of very intensely coloured sapphires onto the market; mainly in the pink-orange spectrum – stones that were like the very expensive padparadscha sapphires. The stones had been trading for at least 6 months before suspicions began to crystallise enough for serious detective work to begin.
Beryllium treated sapphire, photo GIA, Elizabeth Schrader
Two halves of the same sapphire; the left untreated, the right beryllium treated, photo credit GIA, Elizabeth Schrader
The main problem was that the gem treaters denied strongly that anything new had been introduced. The GIA dedicated a huge amount of time to running their own experiments and concluded that these gems had been heated in the presence of beryllium. The treatment was a form of lattice diffusion, but unlike with titanium diffused stones, the colour penetrates a great deal further and sometimes right through the stones. This makes it much harder to detect. The process introduces yellow, orange and brown components into stones, which results in bright yellow and orange colours from pale corundum, the alteration of pink sapphire to padparadscha, the conversion of bluish ruby to a fine red, and it can also reduce dark tones in blue sapphire to make it a better blue. Initially they faced continuing denial from the gem treaters but through a series of their own experiments they were able to reproduce all of the colours that had been seen and considered suspect on the market. In 2003 the Chanthaburi Gem and Jewelry Association finally admitted to the practice.
Why is it a problem?
The issue is that it taking poor or low quality material and by infusing another chemical and heating to just below the melting point of the stone is considered crossing a line. It goes beyond enhancement as it alters the chemical state of the stone and to put it bluntly, attempts to make a silk purse out of a sow’s ear. What is the problem with that? Well some might say, what’s the issue if the treatment is disclosed? It results in lower-priced stones, and as long as everyone knows what they are getting, what is the problem? The trouble is that the treatment is very hard to detect. It cannot be detected using any standard gemmological treatments and in fact there are only a few gemmological laboratories in the world that can detect the treatment, as it requires a particular kind of laser treatment in order to take samples of the material and test it (LIBS (Laser Induced Breakdown Spectrometer) and LA-ICP-MS (Laser Ablation Inductively Couple Plasma Mass Spectrometer). Labs that do not have the equipment will often state on their reports ‘not LIBS tested’. The issue is not confined therefore to dishonest dealers, but since gems change hands so many times between mine and final customer, information might be lost along the way. You might end up with BE stones without realising it. The person who sold them to you might not realise it. The person who sold them to you might not understand the issues and importance of disclosing it and simply fail to mention it. Someone who doesn’t know much about gemstones might pick up a BE treated stone on their travels, think ‘oh what a bargain’ and then sell it on as if it were not treated, because they simply don’t know that they don’t have a bargain, they have a stone that is worth less than it looks. Once a stone is set, it is hard to evaluate it anyway, and someone who has bought a piece of jewellery may fail to mention it if they sell it on, or give it or bequeath it.
So how do you know?
As I’ve mentioned, it is extremely hard to detect this treatment, and requires specialist gemmological equipment for a definite diagnosis. However, there are indications to the treatment that can be made with standard equipment and a bit of common-sense.
Price: The most obvious one. Pay attention to the standard advice: if it looks too good to be true, it probably is. BE treated sapphires cost a great deal less than untreated stones, so be suspicious of any stones that seem a great deal cheaper than they should be
Colour: BE treatment results in very intense colours. Intense orange and yellow sapphire is very rare in nature so if you are seeing a lot of stones like this, it may be an indication that it is BE treated. This is not definitive as sapphire occurs in all colours, including bright yellow and orange. But if it is natural, it is rare, and it ought therefore to be very expensive. Some reports have estimated that most of the yellow and orange sapphire on the market is now BE treated, so some suppliers (myself included) simply do not touch any of it. Better to be safe than sorry.
Microscope inclusions: with this treatment, corundum is treated to close to its melting point. Normally with heating, you can see evidence in mineral inclusions in the stone, eg halo fractures. With BE treatment, these inclusions will look destroyed; crystal forms turned into irregular masses, often with a crackled appearance and a gas bubble in the centre. This has not been observed with standard heating so it’s a good indication that BE treatment has taken place. You also might see synthetic crystal over-growth on the stone.
‘Rims’ or ‘rinds’ on the stone. You’ll need a liquid called methylene iodide, but if you immerse a BE treated stone in this, you’ll often see a different coloured rim or rind on the stone. However depending on how deeply the beryllium has penetrated the stone, it may not always be obvious. So whilst if you do see it, you can be pretty sure that the stone has been BE treated, its absence does not prove no BE
If you come across any of these indicators, especially if you are buying a large, expensive stone, it is imperative to get a full appraisal from a qualified lab.
Proceed with caution. BE treatment has been implicated in most colours of corundum. Check carefully on the descriptions of all stones you are buying, and ask about BE treatment before buying. I have seen it noted on some websites as ‘Be heated’ under treatment, and no, this is not just rubbish English, it indicates BE treatment. I think it is misleading as I am sure that many people see that and think it indicates simply that the stone is heated. Buying from a large, reputable dealer is important, as even with their small stones that are not worth enough to warrant an individual appraisal report, they will periodically test their rough to check it is not BE treated. I source my stones from such a supplier, and they have told me they stock no coloured sapphire, as so much of it is BE treated, it often comes mixed in with untreated material in the bags of rough, and so to be safe, they do not stock it at all. Although BE treatment has been used for blue sapphire, it is far less common and my supplier has not yet detected it in any of the rough they have bought. For this reason, I will be supplying no coloured sapphire in my store. To shop my range, click here
Actually, the green-eyed monster pretty perfectly describes my feelings whenever I see a piece of tsavorite garnet, whether it’s in jewellery or not. It’s my favourite green stone and I’m sorry, for my money, it beats emerald into a cocked hat. It’s bright green, extremely brilliant and unlike emerald, it’s not routinely treated. Tsavorite garnet, in case you don’t know is the transparent lime-green to emerald green variety of grossular garnet, and actually, the colour is due to the same minerals that colour emeralds – chromium or vanadium. A relative newcomer, it was discovered in the 1960s and is mined in Kenya and Tanzania. It’s hard to find in large sizes, in fact the finest emerald green colour rarely occurs in crystals larger than 2 carats, and so larger stones are therefore a great deal more expensive. Smaller stones are not too expensive, however, and in fact it works really well in pave settings as it is so brilliant.
For centuries, garnet has been thought of as a travellers stone; according to legend Noah’s ark was supposed to have a garnet lantern to help with navigation. In particular, garnet is supposed to promote strength, vitality and positivity, so you really can’t go wrong! We have tsavorite garnet rose cuts in small sizes – 2mm, 3mm and 4mm, starting from $4.25 for a 2mm stone, and I will be listing a few 5mm stones in the next few days. You can browse the collection by clicking here.
This is one of my favourite stones, and the most valuable of the red garnets. Rhodolite garnet has a colour range between pinkish red and deep raspberry pink and it’s not just a colour call that distinguishes it from other red garnets; it is to do with its composition. It’s a mixture of pyrope and almandine garnets, with its own distinctive refractive index, and it tends to come up a bit cleaner than almandine. Although its plentiful and reasonably priced, garnet does generally have a high specific gravity – what does this mean? It means that it’s dense and stones are relatively heavy for their size.