Turquoise is an opaque, blue-to-green mineral that is a hydrated
phosphate of copper and aluminium.
The substance has been known by many names, but the word turquoise, which dates to the 17th century, is derived from the French turques for "Turks" because the mineral was first brought to Europe from Turkey from mines in the historical Khorasan Province of Persia.
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About Turquoise. While only ranking between 5.0 and 6.0 on the Mohs Scale of hardness, turquoise remains quite popular for jewellery. In Europe, turquoise rings are given as forget-me-not gifts, while in the United States, the stone is given as traditional 5th and 11th wedding anniversary gifts.
Avoid exposing turquoise jewellery to hot water, household chemicals and ultrasonic cleaners.