Illustration: GOLD (‡ NUGGET).
Gold is the heaviest of the metals with the exception of Platinum,
being rather more than nineteen times heavier than water; it is of
a bright yellow color, and is not tarnished by exposure to the air
or moisture, hence its usefulness in ornamenting frames, cornices,
&c. Gold is chiefly used, in the form of coin, as the medium of
exchange; for ornamental purposes, such as jewellery; for gilding,
and for staining glass, to which it gives a beautiful ruby-red color.
Gold coin contains about one twelfth part, by weight, of copper,
this is added to give it hardness and consequently cause it to lose
less by wear in use. Gold is not dissolved by any of the pure acids,
but a mixture of hydrochloric and nitric acids will dissolve it in
consequence of giving out chlorine, an element which freely dissolves
gold.
Gold is capable of being beaten out into leaves of extreme thinness,
and also of being drawn into wire of such thinness that five hundred
feet of it weigh but one grain.