140 The Zircon, Hyacinth, or Jacinth.
the
East Indies, and New Granada ; also in the river Espailly in France, in
the Iser in Bohemia, and in many places in North America. Specimens of
the hyacinth have been found in the lava of Vesuvius.
This
gem is seldom used for the purposes of jewellery, although a solitary
specimen, when free from defects, and of a fine colour, may realize a
high price. It is sometimes confounded with the eponite or
cinnamon-stone, but is totally different in the most important
characteristics.
When
the hyacinth is of a greyish or smoky-white colour it is called a
jargoon, and is frequently sold for diamond, which gem it approaches
more nearly than any other in lustre. In the last century the jargoon
was supposed to be an inferior diamond, and was much used in mourning
ornaments. It is found in great abundance at Matura, in the island of
Ceylon, whence the natives give it the name of Maturan diamond. It is
rarely found of large size, generally not exceeding ten to twelve
carats in weight.
This
gem possesses the characteristic of double refraction to a very high
degree, and does not acquire electricity by heat. The jargoon occurs of
several colours, and is rarely perfectly transparent.
The
hyacinth or zircon, and jargoon, are identically the same stone,
differing only in colour. The red varieties are sometimes sold for
inferior rubies, although they almost always have a more yellow tinge
than the ruby.
The word "zircon" is supposed to be derived from
