Amber
This fossil resin, yellow and brownish-yellow in tint, finds an extensive use as the material for mouthpieces of pipes, cigar and cigarette-holders, umbrella-handles, and so on, and is even locally cut for jewellery, although its extreme softness, its hardness being only 2½ on Mohs’s scale, quite unfits it for such a purpose. It is only slightly denser than water, the specific gravity being about 1·10. Since the structure is amorphous the refraction is single, the index being about 1·540. Amber, being a very bad conductor of heat, is perceptibly warm to the touch. Its property of becoming electrified by friction attracted early attention, and from the Greek name for it, ἤλεκτρον, is derived our word electricity.
Amber is washed up by the sea off the coasts of Sicily and Prussia, and of Norfolk and Suffolk in England. The finest examples, which are picked up off the shore of Catania in Sicily, are distinguished by a fine bluish fluorescence, resembling that seen in lubricating oil; such pieces command good prices.
A recent resin, pale yellow in colour, known as kauri-gum, is found in New Zealand, where it is highly valued.
TABLES