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Exotic Mineralogy
Phosphate of Manganese
- Syn.
- Manganèse phosphaté (ferrifère). Haüy, Tabl. 111.
- Phosphate of Iron and Manganese, Pitchy Iron ore. Thompson, IV. 482.
This mineral is brought from Limoges, where it occurs in a Quartz vein in Granite. It is found massive, and breaks into large flattish fragments, the surfaces of which are covered with a dull ferruginous stain, resembling tliat in the fissures of various flinty and other substances. In the purer parts it has a shining resinous fracture, with some transparency, and a deep brown colour; it is imperfectly laminated in two directions perpendicular to each other. Haüy has observed also, that it is divisible with difficulty parallel to the base of a rectangular prism. It is brittle, and yields easily to steel; its powder is nearly white; by the help of the blow-pipe it melts into a black enamel. Spec. Grav. 3.956.
| Oxide of manganese | 42 |
| Oxide of iron | 31* |
| Phosphoric acid | 27 |
| 100 |
I am indebted to the liberality of Sir Joseph Banks for the specimen figured, who gave it me several years ago; it is accompanied by decomposing Feldspar and green Mica.
I suspect that this substance, which is at present rare, maybe found more commonly, but there is nothing sufficiently attractive in its appearance to tempt analysis, but science does not always look to showy appearances.
- * Mr. Darcet, jun, has shown that some specimens which are redder than others, contain a much less portion of iron, hence the iron may be considered as accidental.
