Amber is principally obtained from the shores of the Baltic, but it is also found in other parts of Europe. The most esteemed is the opaque variety, resembling the color of a lemon, and sometimes called fat amber; the transparent pieces are very brittle and vitreous. The German pipe makers, by whom it is principally used, employ thin scraping tools, and they burn a small lamp or place a little pan of burning charcoal beneath the amber to warm it slightly whilst it runs in the lathe. This prevents it from chipping out, but if it is too highly heated by friction it is apt to fly to pieces.
The finer specimens of amber, which are sometimes formed into gems and ornaments, are ground on lead plates made to revolve in the lathe, any of the usual abrasive substances (sand or emery) being used. The facets are then finished by means of a whetstone, and polished with chalk mixed with water or vegetable oil. The final finish is given by means of flannel. During the polishing process the amber becomes very warm and highly electric, and if this heating goes too far it will fly in pieces. The workmen, therefore, cool it off every now and then.
Coat with linseed oil the surfaces that are to be joined; hold the oiled parts carefully over a charccal fire, a few hot cinders or a gaslight, being careful to cover up all the rest of the object loosely with paper. When the oiled parts have begun to feel the heat so as to be sticky, press and clamp them together and keep them so until nearly cold. Only that part where the edges are to be united must be warmed, and even that with care lest the form or polish of the other parts should be disturbed; the part where the joint occurs generally requires to be repolished.
Of late, an imitation of amber, which cannot be distinguished from the genuine article by inspection, has made its appearance on the market. It contains copal, camphor, turpentine, and other ingredients, becomes electric by friction, and is used for manufacturing mouthpieces for pipes, cigar-holders, ornaments, etc. The composition may be distinguished from genuine amber by its lower melting point, as it quickly softens and melts when laid on a hot plate, while amber requires a comparatively high heat; and further by the action of ether, which softens the imitation until it may be scraped away with the finger-nail, while true amber is absolutely insoluble in cold ether.