A hard, solid, semi-transparent substance, found in several mines of Prussia, in a bed of argillaceous mineral. It is also found in Poland, France, Italy; on the shores of the Baltic and Mediterranean, in the neighbourhood of London, and in various other parts. It is generally considered to be of vegetable origin, and to be composed of bituminous vegetable matter in a state of congelation. The extraordinary property which amber possesses of attracting, when excited by friction, light bodies, such as feathers, bits of paper, pith, dust, etc, was known to Thales, the celebrated philosopher of Miletus, who flourished 600 years before the birth of Christ. The Greek term for amber is election; and from this word is derived the title of our modern science, electricity, the effect of excited amber in attracting light substances, being attributed to its elective powers. This mineral is found of various colours, but the most abundant is of a deep yellow or orange. When broken, the fracture is smooth and glossy, and it is susceptible of a beautiful polish. If gently rubbed, it emits a peculiar and agreeable odour.

At a temperature of 550° Fahr, it melts, and its transparency is destroyed.

It is insoluble in water; but alcohol, if highly rectified, extracts a small quantity of its colouring matter. Sulphuric acid will dissolve it, and it may be then precipitated by water. Pure caustic alkalies also dissolve it, and some of the essential oils. Various specimens of amber have been found containing portions of animal, vegetable, or mineral matter, imbedded in the mass. This fact seems to prove that it has once been in the fluid state. From the appearance of insect remains in amber, it would seem that they have attempted to escape from a viscid or congealing mass. In some, the legs, or wings, only, have been found, which seems to prove that the animal has been entangled in the viscid mass, and has left the fragile parts of the body in attempting to wade through it. Drops of water, leaves of plants, native gold, silver, and various other substances, have been found imbedded in amber. Dr. Girtanner promulgated a very ingenious opinion on the formation of amber, which appears plausible. He imagined that a species of ant called formica rufa, formed this substance by the deposition of their peculiar wax, or honey. These ants are found in immense numbers in the pine forests, where amber is obtained in the mineral state.

The wax, although soft, hardens by immersion in salt water, and then bears a great resemblance to amber. Dr. Brewster, however, considers, from the optical properties of amber, that it is established beyond doubt, to be an indurated vegetable juice. By careful distillation, an empyreumatic oil, equal to one-third in weight of the amber, is obtained. This oil is brown and thick if a strong heat is applied, and requires re-distillation; but if the heat do not exceed 212, and water be employed, it is limpid and colourless. It is used in medicine as an antispasmodic. The spec, grav. of amber varies from 1.065 to 1.100. For its use in varnish-making, see Varnish.