Resin

Specific components are alpha-pinene, beta-pinene, delta-3 carene, and sabinene, the monocyclic terpenes limonene and terpinolene, and smaller amounts of the tricyclic sesquiterpenes, longifolene, caryophyllene, and delta-cadinene.

Subfossil copal can be distinguished from genuine fossil amber because it becomes tacky when a drop of a solvent such as acetone or chloroform is placed on it.

Typical rosin is a transparent or translucent mass, with a vitreous fracture and a faintly yellow or brown colour, non-odorous or having only a slight turpentine odour and taste.

[10][11] The word "resin" has been applied in the modern world to nearly any component of a liquid that will set into a hard lacquer or enamel-like finish.

Several natural resins are used as ingredients in perfumes, e.g., balsams of Peru and tolu, elemi, styrax, and certain turpentines.

Plant resins are valued for the production of varnishes, adhesives, and food glazing agents.

They are also prized as raw materials for the synthesis of other organic compounds and provide constituents of incense and perfume.

[12] The hard transparent resins, such as the copals, dammars, mastic, and sandarac, are principally used for varnishes and adhesives, while the softer odoriferous oleo-resins (frankincense, elemi, turpentine, copaiba), and gum resins containing essential oils (ammoniacum, asafoetida, gamboge, myrrh, and scammony) are more used for therapeutic purposes, food and incense.

Important examples are bisphenol A diglycidyl ether, which is a resin converted to epoxy glue upon the addition of a hardener.

Alkyd resins are used in paints and varnishes and harden or cure by exposure to oxygen in the air.