Turquoise

History and lore

Turquoise is one of the earliest gems to have been deliberately mined. In the Sinai peninsula the Egyptians worked deposits at Wadi Maghara and Serabit el-Khadim from at least the early third millennium BCE, and at Serabit they built a temple to Hathor, honoured there as "Lady of Turquoise". The Egyptian word mefkat covered turquoise and probably some other blue-green materials. In Persia the mines near Nishapur in Khorasan produced, for many centuries, the even sky-blue stone that set the standard for the world; its Persian name firuza (or pirouzeh) is commonly connected with victory. The English name is French, turquoise, "Turkish", because the stone reached medieval Europe through Turkish and Levantine trade.

In the Americas turquoise was worked independently. Ancestral Puebloan communities at Chaco Canyon in present-day New Mexico gathered vast quantities of turquoise beads and pieces, much of it from the Cerrillos Hills, between about 900 and 1150 CE. In central Mexico the Nahuatl word xihuitl meant turquoise but also "year", "grass" and "fire", and the fire god Xiuhtecuhtli was the "Turquoise Lord". Mixtec and Aztec artists covered masks, shields and ritual objects in turquoise mosaic, several of which survive in European museums. In Tibet and the Himalaya, turquoise (gyu) is still worn in hair, earrings and the elaborate headdresses of Ladakh.

In the traditions

Turquoise has no clear place in the breastplate of Exodus 28 or the foundations of Revelation 21, though some writers have tried to find it there. Medieval and Renaissance European lapidaries, gathered later by Anselmus de Boodt (1609) and George Frederick Kunz, say that a turquoise protected a horseman from falls and that it grew pale when its owner fell ill or into danger. Across the Islamic world turquoise was set in rings and amulets and held to bring good fortune and avert the evil eye; turquoise-blue tile on Persian and Central Asian domes echoes the same colour.

Among the Diné (Navajo), turquoise is one of the four sacred stones of the cardinal mountains, associated with Tsoodził (Mount Taylor), the mountain of the south, alongside white shell, abalone and jet. As a birthstone, turquoise holds December in the older Gregorian lists and in the American list of 1912, which also gave lapis lazuli; zircon and tanzanite were added later. Some older lists collected by Kunz place it in June or July instead.

Meaning and symbolism

Across very different cultures turquoise has stood for sky and water, protection, good fortune and safe travel; the colour word "turquoise" itself comes from the stone. A widely repeated modern saying holds that turquoise brings luck chiefly when received as a gift. The belief that the stone changes colour with its owner's health is easy to understand: turquoise is porous, and skin oils, soap and cosmetics really can alter its colour over time. That is a physical effect, not a diagnosis, and scientific studies have not found that gems protect or heal.

The mineral

Turquoise is a secondary mineral that forms in arid regions where water percolating through copper-bearing rocks deposits it in veins and nodules, often within a host rock that shows as a dark "spiderweb" matrix. Copper gives the blue, iron the greener tones. Important sources are Iran, Egypt's Sinai, the American Southwest (Arizona, Nevada, New Mexico), China (notably Hubei) and Mexico.

With a hardness of 5–6 and a porous texture, much turquoise sold today is stabilised with resin, dyed, or "reconstituted" from powder; imitations include dyed howlite and magnesite, glass and plastic. Only laboratory testing reliably detects treatment. Keep turquoise away from oils, perfume, cosmetics, heat and ultrasonic cleaners, and wipe it with a soft dry cloth after wearing.

Sources and further reading

• Gemmarum et lapidum historia — Anselmus de Boodt, 1609
• The Curious Lore of Precious Stones — George Frederick Kunz, 1913
• Gems and Precious Stones of North America — George Frederick Kunz, 1890
• Ancient Egyptian Materials and Industries — Alfred Lucas, 1926
• Gems: Their Sources, Descriptions and Identification (6th ed.) — Michael O'Donoghue (ed.), 2006