Resins can be natural, prepared natural or synthetic. The form can be solid or semi-solid. 'Dr' Dee's does not deal with synthetic resins; however, they are described here for your information.
Natural resins are extrudents (or amorphous secretions) from trees. Examples are mastic, pine, fir and tropical trees. Industrial applications use them as binders in varnishes, plastics and printing inks. See Dragon's Blood, Frankinsence,
Prepared natural resins are oleoresins from which the essential oil has been removed. Oleorisens are almost entirely a mixture of essential oil and resin. Oleorisens can be a natural exudation from plants (myrrh) or an aromatic liquid preparation extracted from botanical matter using solvents. Resinoids are perfumery material very similar to oleorisens being extracted with a hydrocarbon type of solvent. These resinoids are prepared from natural resionous matter, such as balsams, gum resins, "cured" vanilla beans, etc. The sandalwood resin that 'Dr' Dee's offers is made in Mysore, India by monks in a monastery from the powered wood and has a gold color. See Sandalwood.
Synthetic resins are prepared by polymerization and are used as used as plastics, varnishes, in adhesives and in ion exchange. Even though these synthetic resins usually have some physical properties similar to the natural resins, they are different chemically.