Lac is the scarlet resinous secretion of a number of species of Lac-producing insects, the most commonly cultivated of which is Kerria lacca.
The lac-producing insect is also known by numerous synonyms such as Laccifer lacca, Carteria lacca and Tachardia lacca. Kerria lacca belongs to the lac insect family Kerriidae, one of some 28 families of scale insects and mealy bugs comprising a large group of about 8000 described species of plant sucking insects, a few of which produce similar natural products (e.g., cochineal and crimson). Thousands of these tiny insects colonize branches of suitable host trees and secrete the resinous pigment. The coated branches of the host trees are cut and harvested as sticklac.
The harvested sticklac is crushed and sieved to remove impurities. The sieved material is then repeatedly washed to remove insect parts and other soluble material. The resulting product is known as seedlac. The prefix seed refers to its pellet shape. It is used in violin and other varnish and is soluble in alcohol. This type of lac was used in the finishing of 18th century fowling guns in the US. Seedlac which still contains 3-5% impurities is processed into shellac by heat treatment or solvent extraction.