Muriate of Iron

There have been two specimens of this curious mineral brought to England by Dr. Gmelin of Wurtenberg; the largest was presented by him to the British Museum, whence I have obtained the figure. It is a Muriate of Iron, combined with a small portion of Silex, which defends it from the action of water, although it is soluble in muriatic acid: before the blowpipe chlorine is liberated in pungent fumes, whence it has been called Pyrosmalite, leaving a magnetic globule. It was discovered in Bjelke’s mine, in Nordmark, Wermeland, in a bed of Magnetic Oxide of Iron, accompanied by Carbonate of Lime and Hornblende. The specimen in the Museum is about half of an hexahedral prism, lying upon its side among foliated Carbonate of Lime upon a greenish earthy stone, in the fissures of which are minute crystals of Hornblende. The end of the prism is fractured; it has a pearly lustre resembling pinite, and exhibits laminæ perpendicular to the sides: the cross fracture is splintery; in some parts it is semi-transparent, and rather browner than in the opaque parts.