Dammar is a generic term for a number of different resins, of which East Indian or Singapore dammar is the only one that appears on the English market in quantity. East Indian dammar is derived from the Amboyna pine, Dammara orientalis, Lamb. (N.O. Coniferae), which is cultivated in the Eastern Archipelago. Dammar occurs in nodules 3 to 6 millimetres in diameter, but sometimes larger; the exterior is coated with white powder, while the interior is pale amber coloured, transparent or translucent. It is readily friable and adheres only feebly on warming in the hand. It softens at about 100° and melts at about 150° to a clear liquid. The fracture is conchoidal and vitreous and usually exhibits air bubbles and vegetable debris. The odour is balsamic when the resin is fresh, but afterwards imperceptible. Specific gravity, 1.062 to 1.123. The following has been given as a test for purity:—If 50 mils of benzene be poured on 1 gramme of finely powdered dammar and 20 mils of semi-normal solution of potassium hydroxide be added, and the mixture be set aside, well corked, for twenty-four hours, on titration with phenolphthalein as an indicator 19 to 19.3 mils of semi-normal sulphuric acid should be required, corresponding to an acid number of 20 to 30. The yield of ash on ignition should be almost infinitesimal. Dammar is sometimes known as Manilla copal or mastic. Rock dammar, obtained from Shorea species, is sometimes imported, and closely resembles the above, but may be distinguished by its insolubility in 60 per cent. aqueous solution of chloral hydrate, in which all coniferous resins are soluble. Kauri resin is sometimes called New Zealand dammar (see Copal).
Partly soluble in cold alcohol, moderately soluble in ether, soluble in boiling alcohol and fixed and volatile oils, chloroform, carbon bisulphide, and petroleum spirit; insoluble in acetic acid and alkalies.
Constituents.—Dammar consists mainly of a mixture of resins and resin acids, but also contain, small quantities of a bitter principle and a volatile oil.
Uses.—The principal use of dammar is in the preparation of varnishes, but it is occasionally used as a constituent of plaster masses.