The sapphire, the blue variety of corundum, is mentioned in the Bible as being the second stone in the second row of the high priest’s breastplate, and again in the Book of Job as a precious stone; but there is some doubt whether the modern sapphire is, in either place, referred to. Sapphire is usually found with the ruby and other forms of the corundum, but in Siam sapphire is more common than in Burma.

The method of winning both gems from the surface gravel is similar and simple. The gravel is excavated and carried off in baskets by men working in small parties of three or four. In Burma, however, hydraulic machinery and other scientific improvements have been introduced, but this forms part of the romance of mining. After washing the gravel, the gems are picked out by hand, usually by Europeans, and sorted into about a dozen different qualities. The best come to the London market, the others are sold by atiction fortnightly to local dealers.

A large amount of corundum gems of inferior quality is used for making jewelled bearings of watches and for various electrical instruments ; a small amount is also used for wire-drawing. For such purposes colour and transparency are of little account, but the minerals must be pure, free from parting planes and must break with a conchoidal fracture. Over 20,000,000 of watch jewels are sold annually.