Physical Characteristics and Location of Jet

Jet, a beautiful black substance, is in point of fact a lignite produced by the decomposition of resinous vegetation buried in the earth thousands of ages before the historic times. Yet in mines of lignite jet is rare.

The hardness, the fineness, and the compactness of its tissue probably result from the peculiar nature of the trees from which it has arisen. However this may be, it is the union of these qualities that render jet capable of receiving a very brilliant polish, and assert its place as a valuable object of jewelry.

Jet is found in all places where amber exists, and in many localities also where amber is not found.

Jet was formerly much more highly valued than at present. In the last century, Aude, in France, alone employed 1200 workmen on this substance. At Whitby, in Yorkshire, jet is still the object of a considerable industry. But the imitations of this substance have largely taken its place; even the poor imitation of varnished glass is received with favour. A much better substitute for it would be real stones of little value, such as black tourmaline, melanite, and obsidian.

Jet is worked by means of a lathe and horizontal sandstone wheels, smooth at the centre, but rough at their circumferences, so that the workman may cut and polish a stone on the same wheel.

Among ancient ornaments of jet are some curious anklets and bracelets belonging to the early period of British history.