THE TURQUOIS.

Wairarapa Daily Times, Volume VIII, Issue 2367, 7 August 1886, Page 1 (Supplement)

THE TURQUOIS.

The turquois is called in chemical language a hydrated phosphate of alumina, This means that it consists oiaiuly of phosphoric acid and alumina, along with nearly 20 per cent of water. It owes its color to small quantities of compounds of copper and iron. It occurs h]n£ ( green, and bluise green, hut the change to a pale, mottled, or white color, whioh iuferior turquoises undergo, generally takes place soon after they are taken from the mine, These colors are opaque, or only very slightly translucent, and the stone haß a somewhat waxy lustre It is only thuseof a fast " sky-blue" color that are prized for jewelry; but at one time a' green turquoise was more highly valued than a blue one. Nowadays, however, people have no patience with either precious stones or precious metals than can be eatily mistaken for those of inferior value,' Either green feldspar, which is of the same hardnoss, or malachite, which is softer, might be mistaken f*r green turquois, and both are more common minerals. But there jb hardly any other natural stone of the same, or even inferior, hardness that can be confounded with a blue'turquois, The material of some fossil teeth when colored with phosphate of iron does, however, resemble it. Still, there need be no confusion, 'because this substance is softer. It is called odontolitcor Occidental turquois, while the real stone ia known by jewellers as the Oriental turquois, Odontolite is easily recognised under the microscope by the characteristic markings of den- ' tine.