government
buys a large quantity for making altars, sacred vessels, etc. The
Chinese merchants usually purchase then-jade at Mogaung, Hpaka, Hweka
and other mining centres. Mandalay is the centre for cutting jade in
Burma and commands the largest market for its jewellery.
Future trend
The market for jade depends largely on the Chinese market, and thus depends on the conditions in China.
Chapter XXIII
TURQUOIS
Introduction
TURQUOIS
is supposed to have derived its name since it was exported from Turkey
through Persia. The mineral is also found in Turkestan. It has a
distinctive blue colour, which forms an agreeable contrast in a gold
setting. It is apparently amorphous, but has been found to be triclinic
recently. The Virginian turquois has been found to be crystalline as
very small crystals. Fracture con-choidal. Hardness = 6. Specific
gravity =2.6 to 2.8 Usually opaque with a waxy lustre. Colour varies
from greenish grey, yellowish green, apple green to greenish blue and
sky blue. The blue colour is due to copper and the green due to iron.
Sky blue turquois is most valued. On account of its porosity, it
becomes dirty very easily. Refractive index = 1.63. It has a complex
composition of
a basic phosphate of copper and aluminium. • Ferric iron may replace part of the aluminium.
Uses
It is valued in jewellery due to its blue colour forming an agreeable contrast to the gold setting.
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