Source, Etc

Sandarac is a resin obtained from Callitris quadrivalvis, (N.O. Coniferoe), a small tree about 7 metres high, growing on the mountains in the north-west of Africa. It is usually obtained by incision, the tears when sufficiently hard being collected and exported, chiefly from Mogadore.

Description

Sandarac occurs in small tears about the same size as mastich, but usually of an elongated, more or less cylindrical or stalactitic form, several of which are sometimes united into a small, flattened mass. Globular or pear-shaped tears are comparatively rare in it, and by this means it can be distinguished at sight from mastich.

The tears, as usually seen in commerce, have a dull dusty surface and a pale yellowish colour; they are brittle, breaking with a glassy conchoidal fracture, and displaying a clear, transparent interior, in which, as in amber, small insects are occasionally embedded. The resin has a slight terebinthinate odour and a terebinthinate, slightly bitter taste; when chewed it breaks up between the teeth into a sandy powder which, unlike mastich, shows no disposition to agglomerate into a plastic mass.

It is completely soluble in alcohol and ether, partially only in chloroform, carbon disulphide, and oil of turpentine.

The student should observe

(a) The preponderating stalactitic form,

(b) The terebinthinate odour,

(c) The indisposition to form a plastic mass between the teeth; and should compare this drug with

(i) Mastich (see p. 468), (ii) Olibanum (see p. 481).

Constituents

Sandarac consists of resin associated with traces of volatile oil, bitter principle, etc. The chief constituent of the resin is (optically) inactive pimaric acid (sandaraco-pimaric acid, 85 per cent.), obtainable in acicular crystals melting at 170°; other constituents are sandaracinic acid (2.3 per cent.), amorphous callitrolic acid (10 per cent.), and sandaracoresene. Callitrolic acid is easily converted into the lactone which is insoluble in alcohol.

Uses

Sandarac is chiefly used in the manufacture of varnishes; it is paler in colour than shellac, and is therefore more suitable for light woods.

Varieties

Australian sandarac, from C. verrucosa, Robert Brown, is occasionally imported. The tears are softer, larger, and more aromatic than those of African sandarac, which it otherwise resembles. Its composition is similar, but it contains more volatile oil and more inactive pimaric acid.