Amethyst, the violet-to-purple variety of macrocrystalline quartz (SiO₂), is the universally recognised birthstone for February, appearing in both the modern standardised list adopted by the American National Retail Jewelers Association in 1912 and in older traditional lists stretching back through medieval lapidary tradition. Its colour, produced by iron impurities and natural irradiation within the crystal lattice, ranges from pale lilac through rich grape-purple to the deep reddish-violet stones prized under the trade descriptor Deep Siberian. Among the most widely worn and commercially accessible of all coloured gemstones, amethyst occupies a position of genuine historical prestige that long predates its current affordability.

Historical and Symbolic Associations

The name derives from the ancient Greek amethystos, meaning "not intoxicated" — a reference to the classical belief that the stone protected its wearer against drunkenness. Goblets were carved from amethyst or lined with it for this supposed prophylactic purpose. The gem was among the most valued stones of antiquity, ranked alongside ruby and emerald in the treasuries of Egyptian pharaohs and set into the breastplate of the Hebrew high priest. Its association with February is reinforced by the feast day of Saint Valentine, whose traditional iconography sometimes includes an amethyst ring engraved with the figure of Cupid. In Christian ecclesiastical tradition, amethyst became the stone of bishops and cardinals, symbolising piety and celibacy; the colour purple itself carried connotations of royalty and spiritual authority across multiple cultures.

Gemological Properties

As a variety of quartz, amethyst shares the species' fundamental characteristics: a hardness of 7 on the Mohs scale, a trigonal crystal system, and a refractive index of approximately 1.544–1.553 with a birefringence of 0.009. The specific gravity is approximately 2.65. The colour is caused by Fe³⁺ ions substituting for silicon within the crystal structure, activated by natural gamma irradiation; this mechanism is directly relevant to the gem's sensitivity to heat and light. Amethyst is typically eye-clean, though natural colour zoning — often appearing as angular or sector-shaped bands of deeper purple — is characteristic and does not diminish value in the way inclusions might.

Principal Sources

Historically, the finest amethyst came from the Ural Mountains of Russia, and the term Siberian remains a quality descriptor for deeply saturated stones with reddish-purple secondary hues, regardless of actual origin. Today the dominant sources are:

• Brazil — particularly the Rio Grande do Sul and Minas Gerais states, which supply the majority of the world's commercial amethyst, often in large geodes.
• Uruguay — renowned for smaller crystals of exceptional depth of colour, often with a distinctly bluish-purple tone.
• Zambia — producing stones with strong saturation and a characteristic reddish secondary hue, increasingly valued in the fine-gem market.
• Madagascar, Bolivia, and Sri Lanka — additional sources of varying commercial importance.

Treatment and Stability

Amethyst is routinely sold without treatment, and untreated material requires no disclosure. However, two treatments are relevant to buyers and owners. First, heat treatment at temperatures above approximately 300–400 °C converts amethyst to yellow or orange-yellow citrine, or to the greenish variety known as prasiolite; much commercial citrine is in fact heat-treated amethyst. Second, and critically for wearers, amethyst is susceptible to colour fading upon prolonged exposure to ultraviolet radiation and strong sunlight. This fading is permanent and irreversible, as the UV energy disrupts the iron-colour centres responsible for the purple hue. Jewellery set with amethyst should be stored away from direct sunlight and should not be worn during extended outdoor exposure in bright conditions. Cleaning with mild soap and warm water is safe; ultrasonic cleaners are generally acceptable for eye-clean stones without fractures, but steam cleaning should be avoided due to thermal sensitivity.

In the Trade and as a Gift

Amethyst is one of the few genuinely fine-coloured gemstones available at accessible price points across a wide range of sizes, making it a practical as well as meaningful choice for February birthstone jewellery. The finest specimens — deeply saturated, well-cut stones from Zambia or Uruguay in sizes above five carats — do command premium prices in the coloured-stone market, though they remain far below the per-carat values of ruby or fine sapphire. Amethyst is also recognised as the gemstone for the sixth wedding anniversary. When selecting a stone, buyers are advised to prioritise colour saturation and evenness over size; the most desirable hue is a strong, slightly reddish purple with minimal colour zoning visible to the eye in the face-up position.

Further Reading

• GIA Gem Encyclopedia: Amethyst
• GIA: February Birthstones
• AGTA Gemstone Encyclopedia: Amethyst