Amethyst
Until the 1800s amethyst was priced alongside ruby and emerald. Then large deposits were found in Brazil and Uruguay, and it became affordable overnight. Nothing about the stone changed. Only the supply did.
What is amethyst?
Purple quartz. The colour comes from trace iron in the crystal lattice, altered by natural irradiation deep in the earth over a very long time. Same mineral as rock crystal, rose quartz and citrine — the difference is a few atoms and a great deal of geology.
How do you judge amethyst colour?
This is where amethyst is won or lost. The best material is a deep, even purple with red or violet flashes, holding its colour under low light. Weak amethyst goes grey and washed out indoors, and looks noticeably better in a photograph than on a hand.
The subtler problem is zoning: amethyst frequently grows in bands of stronger and weaker colour, and a cutter who orients the stone carelessly leaves a piece that is vivid at one end and pale at the other. Look at a stone face-up under diffuse light and turn it. If a corner drains, the cut was rushed.
Does amethyst fade in sunlight?
Worth knowing and rarely mentioned: amethyst can fade with sustained exposure to strong sunlight. Prolonged heat does the same — that is exactly how amethyst is turned into citrine. A ring worn in daylight is fine. An amethyst left on a sunny windowsill for a year or two may not be the same colour when you come back to it.
Is amethyst durable enough for daily wear?
Mohs 7. Hard enough for daily wear and one of the easiest coloured stones to live with. It is quartz, so it is tough rather than brittle, and it takes a polish that stays sharp for years.
How do you care for amethyst?
Warm soapy water and a soft brush. Avoid steam cleaners and prolonged heat. Ultrasonic is generally safe for clean material but not for stones with visible fractures.
Why is amethyst February's birthstone?
February's birthstone, and the stone most associated with clear-headedness — the Greek name means, roughly, "not drunk", from a belief that a cup carved from it would keep you sober. Optimistic, but it gave the stone a long association with restraint and clarity that has outlasted the drinking.