Sumatra benzoin is obtained from S. Benzoin on the island of Sumatra. It is always exported in blocks, which, like the Siam variety, consist of white tears, compacted together by a resin, but the latter is usually less vitreous in appearance, and of a dull reddish or greyish-brown colour. Fine qualities have a strong storax-like odour, which is quite distinct from the vanilla odour of Slam benzoin. Sumatra benzoin may also be distinguished from Siam by the presence in it of cinnamic acid, which may be detected by boiling a little of the powdered resin with potassium permanganate, when an odour of benzaldehyde will be developed. Some samples of Sumatra benzoin are distinguished by their greyish, vitreous, or glassy appearance, and absence of any perceptible aromatic odour; these are classed as "Penang," or "Glassy Penang" benzoin, and are not suitable for pharmaceutical use. Palembang benzoin is another variety obtained from Sumatra, but from what tree is not definitely known. The drug arrives usually in tins, and consists of a reddish resinous mass, in which a few scattered tears are embedded. It has only a slight odour, resembling that of Sumatra benzoin, and, like the glassy Penang variety, is used chiefly for the production of benzoic acid.