Prized from antiquity for its rich, intense colour, it ranges from a gorgeous sky blue (or as is often described, a robin’s egg blue), through to green. The colouring agents are iron and copper. A pure blue colour is rare, and highly prized. Often its blue is mixed with brown, grey and black veins which many consider enhances its beauty even further. In its natural state it is often mixed with malachite and chrysacolla.
Occurs in fissures as veins in the form of nodules and grape like masses. The best turquoise comes from northeast Iran. Other sources are Afghanistan, Argentina, Australia, Brazil, China and Tibet, Israel, Mexico, Tanzania and the United States.
Turquoise was one of the first gemstones to be mined. Beads dating 5000 BC have been found in Mesopotamia. The stone was extracted from sources in the Sinai Peninsula before the 4th century BC, some of which mines were already worked out 1500 years earlier. The magnificent turquoise adorned breastplate of Pharaoh Sesotris the second (1844-1837 BC), is now in the Metropolitan Museum of Art in New York City. Turquoise was introduced into Europe via Turkey, hence its modern day name. Turquoise is regarded by the Iranians as jade is by the Chinese, and has been prized and worked since antiquity. Persian turquoise tends to be harder and of a more even colour than North American turquoise. It is always sky blue, never green. Some stones are more porous than others and, over time slowly change colour, hence the now acceptable practise of stabilising the stone (with plastic resins) is now fairly common, especially with the raw material from New Mexico and Arizona.
In Persia good luck was thought to come to someone who saw the reflection of the waxing crescent moon on turquoise. In Buddhist mythology it is the colour of healing (as anyone gazing on the azure waters of a tropical beach can probably testify). According to North American Pueblo belief, a piece of turquoise attached to a gun or a bow assured the firer a perfect aim. The stone was also thought to warn the wearer of danger or illness by changing colour, though we now know this is in reality the result of the influence of sunlight, heat, perspiration, oils, cosmetics and household detergents. Turquoise and lapis lazuli are the birthstones for December.