Common Rosin or Colophony is either brown or white. The brown variety is obtained by distilling the turpentine of spruce fir in water; the white is distilled from Bordeaux turpentine.
The principal resins used in good work are as follows : -
Amber, obtained chiefly from Prussia, is a light yellow transparent substance found between beds of wood coal, or, after storms, on the coasts of the Baltic. It is the hardest and most durable of the gums, keeps its colour welL and is tough, but difficult to dissolve, costly, and slow in drying.
Gum Anime is imported from the East Indies; is nearly as insoluble, hard, and durable as amber, but not so tough. It makes a varnish quick in drying, but apt to crack, and the colour deepens by exposure.
Copal is imported from the East and West Indies and America, etc, in three qualities, according to colour, the palest being kept for the highest class of varnish. These become lighter by exposure.
Mastic is a resinous gum from the Mediterranean; it is soft and works easily.
Gum Dammar is extracted from the Kawrie pine of New Zealand, and also from India. It makes a softer varnish than mastic, and the tint is nearly colourless.
Gum Elemi comes from the West Indies, and somewhat resembles copal.
Lac is a resinous substance which exudes from several trees found in the East Indies. It is more soluble than the gums above mentioned.
Stick Lac consists of the twigs covered with the gum. Seed Lac is the insoluble portion left after pounding and digesting stick lac. When seed lac is melted, strained, and compressed into sheets, it becomes Shell Lac. Of these three varieties shell lac is the softest, palest, and purest, and it is therefore used for making lacquers.
Sandarach is a substance said to exude from the juniper tree. It resembles lac, but is softer, less brilliant, and lighter in colour, and is used for pale varnish.