Pieces the size of a head, weighing over 22lb/10kg, have been found. It is sometimes found with inclusions of insects, parts of plants, or sometimes pyrites. It is often turbid because of numerous blisters, hair lines or tension fissures. It is possible to clear air bubbles and enclosed liquids from the material by boiling in rape-seed oil, thus improving the quality.
Reaction to chemicals are hot solutions varies to origin. Can be ignited by a match. When rubbed with a cloth, amber becomes electrically charged and can attract small particles. Takes polish well, and has a resinous luster. Mined from the surface, the amber is picked and washed out. Only about 15% is suitable for jewellery. The remainder is used for pressed amber or melted for technical purposes.
There are large reserves on the seabed of the Baltic. After heavy storms, amber is found on the beaches and in shallow waters, after the surf has stirred up the seabed. This sea amber is especially solid and used to be regularly fished by fishermen.
It has been used since prehistoric times for jewellery and religious objects, accessories for smokers, also as a cure for various illnesses. Amber, the “gold of the North”, is the earliest-used gem material of all. Used today for ornamental objects, ring stones, pendants , brooches and necklaces

*Info by Walter Schumann “Gemstones of the World”