Ametrine is the trade name for bi-colour amethyst; part amethyst, part citrine – see what they did there! In many ways it’s the panda bear of the gemstone world; it only comes from one mine in Bolivia, and given that citrine is effectively amethyst that has been heated, what you are looking for are amethyst crystals which have been partly heated by processes in the earth and partly not. Then you want to find a nice clean crystal that will co-operate and give you an nice gem with a balance of both colours. In the past, the classic cut was a step-cut rectangle with an ideal proportion of 50/50 amethyst and citrine. These days, however, all kinds of arrangements are common. I’ve seen ones where the cut-off runs diagonally through the stone, and fancy cuts and concave cuts scatter the light and create all kinds of interesting colours and effects. I have for sale just a few of the classic rectangular step cuts, with good proportions and also a few concave cuts. Concave cutting is interesting as it involves cutting conical facets with 3 dimensions, so that each facet has depth as well as length and breadth. This means that more light is refracted and the stone appears more brilliant. In addition, the facets create a fascinating effect. To shop the range, click here.
Below, two perfectly simple, perfectly elegant rings, the settings a perfect foil for the beautiful stones. Left; Stone Fever Jewelry’s ametrine and sterling silver ring at $275 and EVGAD’s concave cut ametrine and sterling silver ring at £89
Stone Fever Jewelry Ametrine and sterling silver ring, $275
EVGAD ametrine and sterling silver ring, $89
Or parti-coloured tourmaline, to give it its correct title. Not, as my slightly po-faced GIA instructor said, as in, ‘let’s have a party.’ That may have been a joke. It was slightly hard to tell. New in stock, I have more pieces of this most beautiful and fascinating of stones in a breathtaking array of colours. I have new slices and some rose cut (polki) pieces, and each piece has been hand-selected by me for either its pattern – complex or simple, its colour – unusual or gorgeous, its unusual combinations of colours, or it’s saturation – saturated or subtle. The green and orange polki, top left, or the teal green surrounded by black slice towards the top right; the pale pink and blue polkis, of which I have several, and blue is always a popular colour that goes fast.
Clarity of these stones can be rather mixed, but most of these are not bad and many have the kind of clarity characteristics that I think are rather beautiful; for instance you can see mirror-like inclusions on several of the stones, which sparkle as the light catches them with a spectral flash. Tourmaline crystals are very distinctive; broadly triangular in shape with striations down the sides and the colour zoning is due to a change in the concentration or composition of the trace elements that give the stone its colour during its growth. Iron, titanium and manganese induce different colours and yet others might be due to colour centres caused by radiation. To shop watermelon slices, click here; to shop freeform rose cuts (polki), click here.
So many gorgeous examples of watermelon tourmaline jewellery around, but if I had to pick out one I have long coveted Barbara Heinrich Studio’s watermelon tourmaline slice necklace. This also has hand-fabricated 18k gold shell elements and gold tube spacers. Love those gold shells, echoing the shape of the tourmaline slices, and love the matched-but-not-matched slices.