Turquoise

Copper mineral of sky-blue colour. Can tend to greenish hue. Material varies n consistency from compact to porous to powdery.

Much treatment is applied to improve the colour and durability - by staining and impregnation with wax, resin or colloidal silica. consider turquoise as 'treated' unless theere is evidence suggesting otherwise. Heat and mild acidic substance should be avoided.

Long history of use as a gem material for beads and inlay eg: Egypt and Central America. Now is most often fashioned into beads or cabochons and maybe small carvings.

Sources in Mexico, China and SW USA. Is the national gemstone of Iran where it has been mined since antiquity. Produces gem material of excellent colour that is relatively stable. Diamond mines of Deccan plateau, Nishapur, Northern Iran, had virtual monopoly on turquoise in the early modern period.

Lore: brings food fortune and happiness; changes colour with wearer's health; protect from evil.

Arab Roots of Gemolgy

Some elements from 'Arab roots of gemolgy: Ahmad ibn Yusuf Al Tifaschi's Best Thoughts on the Best of Stones' (c.1240) trans. Samar Najm Abul Huda. The Scarecrow Press, London, 1998.

Caused by copper vapours rising from the host rock. Brought from a mine in the mountains of Nisabur [Nishapur, Iran]. Better than the variety taken from Nishawar/Peshawar.

Two varieties:

• bushaqi - pure, the best kind, radiant blue colour, high lustre and even distribution of colour, found mostly in small stones
• qadjandji

It is a stone of which clears as the sky clears and becomes cloudy with the sky's cloudiness (Aristo said that every stone that changes colour if bad for the wearer.) Grease ruins it and changes it colour, as does perspiration and musk.

It clears the vision is one looks at it. Beneficial for the eyes if powdered and mixed with collyriums. Drunk for stomach pains and for scorpion bites and harmful poisonous creatures. Strengthens drooping eyelids and good for veils obscuring the vision. Repels murder from it holder, and it was never seen in the hands of a murdered man.

Stones differ a lot in quality. Berber emirs of Morocco and their leaders like to acquire this stone and pay high prices for it. They decorate their swords with it and wear it a lot in finger rings. People pretend it is used in alchemy but this is not true - they pay high prices due to what is said about its property of repelling murder. God knows best.