Turquoise is an opaque gem usually found in the bluey-green colours which the name now denotes. It can also be found in other colours, varying from white to an unusual, yellowish green. It is sometimes flecked with pyrite or veined with dark, spidery limonite lines. It is rare and valuable, particularly in finer grades and its unusual colour has meant it has been prized as a gem and ornamental stone for many millennia.

The word turquoise (which is far from the only name the stone has had) was coined in about the 16thC, from the French word either for ‘Turkish’ (Turquois), or ‘dark-blue stone’ (pierre turquin). The former of these is thought to have arisen from a misconception: turquoise does not in fact occur in Turkey, but having been obtained via the Silk Road in China it was traded at Turkish bazaars to Venetian merchants who brought it to Europe. Nonetheless it is true that the colour has been used extensively in the decorative tiles adorning Turkish places of worship and homes for many centuries. Quite possibly it is this association which caused the name to take root.

Because of its colour, the North American Indians believe that this gemstone opens up a direct connection between the sky and the sea.

Turquoise was among the very first gems to be mined, and although many historic sites have been depleted, a considerable number are still worked to this day. These are small-scale operations often worked on a seasonal basis, due to the size and remoteness of the deposits, largely worked by hand with little or no mechanization.

Turquoise has been used for fine jewellery by the rulers of Ancient Egypt, the Aztecs, Persia, Mesopotamia and in ancient China since at least the Shang Dynasty (from 1766 BC). Although it is one of the oldest gemstones, it did not become important as an ornamental stone in the West until the 14thC, when the decline of the influence of the Roman Catholic Church meant people felt able to use it in secular jewellery. It was introduced to India in the Muhgal period (from 1526) and to Japan in the 18thC. In all these cultures it is believed that turquoise has certain prophylactic qualities – that it changes colour with the health of the wearer and protects him or her.

Turquoise has historically been used in combination with a variety of different gemstones. Ancient objects inlaid with turquoise include provocative and presumably ceremonial mosaic objects such as masks (some with a human skull as their base), knives and shields crafted by the Aztecs. This turquoise has been laid in beautiful combination with gold, quartz, malachite, jet, jade and coral. The iconic gold burial mask of Tutunkhamun is also inlaid with turquoise, lapis lazuli,and carnelian The Persian style and use of turquoise in gold jewellery, often with rubies and diamond, was taken to India at the time of the Mughal Empire. Persian turquoise was often engraved with devotional words in Arabic script inlaid with gold – the hardness of turquoise makes it an ideal material for carving in this way. Turquoise treated like this can be found in buildings across India, such as the Taj Mahal.