When I first started out in jewellery, I used to make lamp-worked beads and I sold my jewellery in various shops and galleries. One of the shops always said to me, ‘no green please. People don’t buy green jewellery.’ Well, times have changed and green is definitely having a renaissance. Of course, if you talk about green stones, the first one that comes to mind has to be emerald. I have to say that I am not a massive fan of the big E; why not? Well, it’s a combination of its price and properties. Emerald is generally a very included kind of stone. Most emeralds have inclusions; gas bubbles, liquid inclusions, minerals and fractures. And oh my goodness; the fractures. It’s not known whether emerald is a generally fractured stone, or whether it’s the extreme processes required to get it out of the ground. Either way, what this means is that emerald tends to be fracture filled. Something like 96% of all emerald on the market is fracture-filled. This means that clean emerald is very rare and very expensive, and that cheaper emerald is generally highly included, almost certainly fracture filled and the lustre just isn’t great. Emerald is also a rather brittle stone, and of course, as we all know, fractures will tend to make a stone more brittle; if you have a fracture filled stone, then it will appear much less fractured than it actually is, and therefore – dangerously – appear more stable than it actually is. It’s not a great choice for a ring stone. In recent years, emerald finds in Afghanistan have turned up high quality, intense green and relatively clean stones, but obviously there are issues involved with mining in that part of the world.
If you had to give me a choice, my top pick for a green stone would be tsavorite garnet. It comes in a stunning intense green, it has fantastic dispersion (it’s very sparkly!) it’s durable, free from inclusions and is not generally treated. It isn’t cheap, but small stones are reasonably priced and they have a beauty and brilliance that you just don’t get with emerald. Below is Anderson Beattie’s Opal & Tsavorite Garnet Ring; the opal really brings out the chrome green shade of the tsavorite.
Chrome diopside is another intense green option. It really isn’t well known and that’s a shame as colour-wise it packs a punch. It retains its intensity of colour even in small sizes – conversely this means that the colour can get very closed in large sizes, and really you don’t tend to see this stone above around 8mm.
Tourmaline: ah my favourite stone of all time. Green tourmaline runs the spectrum from aqua blue through to yellow ‘beer bottle’ green, with all shades of green-blue, blue-green, intense chrome green and light green along the way. Additionally, because tourmaline is so pleochroic, you will often get several shades of green in the same stone – the ring below from Disa Allsop is a really clear example of this where you can see the bright green and gold green colours dancing across the stone. I also love the way that Lola Brooks uses this spectrum of greens in her jewellery. Mimi Favre’s triple claw setting ring also demonstrates the colour range of tourmaline and Monika Krol’s asymmetrical green tourmaline pendant highlights the beauty of this stone set in gold.
Peridot runs apple green through to yellow-green. It’s reasonably priced and so it’s possible to have it in much larger sizes. For me its at its best en cabochon in a nice strong setting. It’s not hard to find clean stones but larger stones can be prone to black inclusions. However, if you can find them, peridot can have very characteristic ‘lily pad’ inclusions, which I think are rather beautiful. Below is Barbara Tipple’s Lioness Peridot Torque, whose powerful linesperfectly showcases the beauty of this stone.
And this ring from Tayma Fine Jewellery – a large, highly included peridot which looks knockout in this strong and simple setting.
I have a variety of green stones for sale in my shop; to browse, click here
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.
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