Jamunia: Amethyst Gemstones

Amethyst is quartz coloured purple by traces of iron and natural radiation in the ground. It is plentiful compared with sapphire, which means you can choose a large, clean stone with a confident colour without a large budget.

The finest amethyst is a deep reddish purple, sometimes with flashes of pink and blue as the stone moves. Lighter lilac stones, sold as "Rose de France", are popular too and cost less. Colour zoning is common: look through the side of the stone and you may see bands of darker and paler purple. A well cut stone hides this from the top.

Natural or synthetic?

Synthetic amethyst is grown in labs and turns up in cheap jewellery. It can be very hard to tell apart with the eye alone, so a lab check is the reliable route. Glass imitations are easier: they often show tiny round bubbles and feel warmer in the hand. Amethyst itself is rarely treated, though heat can turn it yellow, which is how much citrine on the market is made.

In local tradition amethyst is sometimes worn as a substitute for blue sapphire where budget is a concern, and many people simply like it as a calm purple stone for a man's ring or a woman's pendant. As the February birthstone it is also a popular gift.

At 7 on the hardness scale, amethyst wears well in rings but can scratch over years of rough use. Long hours in strong sunlight can fade its colour, so store it in a drawer rather than on a sunny windowsill. Soap and water keep it clean.