Turqoise is one of the December birth stones (along with zircons and tanzanite).
Turquoise is a beautiful ornamental stone which has a long history of being used in jewellery. King Tutankhamen’s funeral mask from about 1323 BC was inlaid with turquoise and it was found in Egyptian jewellery as early as 3000 BC. Pliny described turquoise as ‘callaica’, an opaque stone which was uniform in colour. In 1576, the conquistador Bernal Diaz del Casillo noted that the Aztecs of Mexico valued a blue stone called chalchihuitl. The name ‘turquoise’ arose in the 17th century, derived from the French expression ‘pierre tourques’ (‘Turkish stone) as it arrived in Europe via Turkey, mainly from mines in what was then Persia where it was mined for over 2000 years. Iran and Eygpt operate mines today.
Other historical sources of turquoise are Mexico and China. The other important source of turquoise is the USA, particularly Arizona and Mexico. Jewellery dating from around 300AD has been found in Arizona.
Colour can vary from sky blue to a greenish blue, often as a result of where it is mined. Persian turquoise is a sky blue, usually a uniform colour, while turquoise from the US mines has a greenish colour as it contains iron. Turquoise is also very porous and so can darken and turn greener due to perspiration and access to water.
Next week, I will talk about the use of turquoise in antique and Victorian jewellery and about imitations.