In obtaining natural resins commercially, cuts are made in the tree bark, and the globules of liquid resin that flow from the cut are directed by troughs into collecting buckets. Amber is one of many fossil resins that are often collected from ground deposits. Natural resins are yellow to brown in color. They burn with a smoky flame and exude an aromatic odor. Chemically, they differ from one another in detail, but they all contain carbon , hydrogen , and oxygen .
All resins are insoluble in water , as distinguished from the water-soluble gums.
Resins are also soluble in alcohol , ether , and other organic solvent s. Synthetic resins resemble natural resins. The natural resin known as lac is not a plant exudate but is formed by the tiny scale insect, Laccifer lacca, indigenous to Southeast Asia. Lac is deposited on trees and is harvested for the production of shellac. All Rights Reserved Worldwide.