Amethysts are much admired for their
exceptional colour - always the most
important consideration in a coloured gemstone.
Amethyst’s bold purple has contributed to its reputation over the centuries as a favoured gemstone of Kings and Queens. It was used as a gemstone by the ancient Egyptians, largely for intaglios — the finest examples of which can be seen in the Cheapside Hoard. The origin of the name has been the source of much speculation, sometimes scholarly, sometimes romantic, sometimes a bit of both.
The Kariba mine, located in Southern Zambia, is the world’s largest amethyst mine. The deposit produces an estimated 90% of all amethysts originating from Zambia.
Over 500 million years in the making
Brazil, Uruguay, USA (Arizona), Zambia
Amethysts range in colour from vivid purple to shades of mauve, violet and lilac, often with flashes of red and blue – the latter, in particular, is highly desirable and can have a quite magical, mesmeric effect.
The colour should be uniform throughout, and the gemstone should possess good lustre – in the case of amethyst, the desired quality is known as “vitreous”.
Large, transparent pieces of amethyst occur widely in nature, so, whatever your budget, you should be able to find an eye-clean gemstone – that is, one that will appear clean to the naked eye, if not under the magnification of a loupe.
Amethyst is both fairly hard – 7 on the Mohs scale – and fairly tough, so it suits most cuts. A well-cut amethyst creates a lot of sparkle, to the extent that you may not be able to see all the way through it when looking straight down through the centre of the gemstone.
The gemstone should be well proportioned and symmetrical, with no distortions. It should have sharp facet edges and flat faces – reflections should enter the eye at once, not ͞roll͟ across the face – and be free of chips and scratches. Badly cut gemstones tend to maximise weight at the expense of brilliance.
The most common treatment of Amethysts is heat treatment, light stones are often heated to create a deeper hue.
Those Amethyst with a particularly high iron content can also be heated to create heat treated Citrine.