Amethyst

Amethyst is purple quartz, Mohs hardness 7. Before the nineteenth century it ranked with ruby, sapphire and emerald among the “five great gems”; a great Brazilian find brought it down to a semi-precious stone — and today it is one of the few beautiful stones that are large, clean and affordable. It is February’s birthstone.

About Amethyst

Amethyst is purple quartz, coloured together by traces of iron and natural irradiation, Mohs hardness 7 with no cleavage, durable and easy to wear. It is the same mineral as rock crystal, citrine and rose quartz, parted only by trace elements and a history of irradiation.

Why Choose an Amethyst

Amethyst is February’s birthstone; it once ranked with the red, blue and green great gems, yet today it is affordable — which is precisely its rare gift. Before the nineteenth century only royalty and the Church could afford it; then large deposits in Brazil and Uruguay brought it down from a top gem to a semi-precious one. It did not get worse — it got affordable.

History & Famous Stones

Amethyst once ranked with diamond, ruby, sapphire and emerald among the “five cardinal gems”, one of medieval Europe’s most noble stones; and its name carries a legend or two. One riddle-stone, one giant geode:

• The Delhi Purple Sapphire: a “sapphire” in name only — in fact an amethyst. Said to have been looted from an Indian temple in 1857, it was thereafter dogged by misfortune; the collector Edward Heron-Allen sealed it inside seven charm-lined boxes and finally left it to the Natural History Museum in London, where it sits in the vault today.
• The Empress of Uruguay: over three metres tall and about 2.5 tonnes, the largest amethyst geode known — miners took three months to free it from the basalt.

The Truth About Amethyst

Amethyst is judged on colour, not clarity; watch for zoning; heating turns it yellow (most citrine comes this way); synthetics are an open problem.

• Truth one: judged on colour, not clarity (it is usually clean). The trade prizes “Siberian” colour most — a deep purple with red-violet flashes, now a colour grade.
• Truth two: watch for zoning. Colour often runs deep here, pale there, and the cutter’s skill is in placing the deepest colour where it shows most.
• Truth three: natural stones are rarely enhanced; but heated amethyst turns yellow, and most citrine on the market comes exactly this way.
• Truth four: synthetic amethyst is an open problem. Hydrothermal synthesis is mature and hard to tell by eye or basic testing.

Amethyst on the Market

Guard against synthetic amethyst and glass / cubic-zirconia imitation, and watch for pale stones sold as deep.

Type	Traits	Price	How to tell
Natural amethyst	Even colour, usually clean	Affordable	Natural zoning
Synthetic amethyst	Hydrothermal, too perfect	Low	Hard by eye, needs instruments
Glass / cubic zirconia (CZ)	Glass has bubbles, CZ too bright	Low	Bubbles, over-heavy or over-bright
Pale sold as deep	Shows colour under lamps	—	Judge in daylight

Before You Buy

Amethyst fades in sun — avoid prolonged direct sunlight; otherwise it is easy to keep, cleaned with warm soapy water.

• Amethyst fades in sun: prolonged direct sunlight pales the purple, irreversibly — off the windowsill, and not worn in long sun.
• Beyond that it is easy to keep — hard, no cleavage, warm soapy water will do.
• Look for even colour, from several angles; avoid stones coloured in only one corner.
• Do not pay a cent extra for added mystical claims.