Hæmatitic Sulphuret of Lead, or Hæmatitic Galena

I have heard it remarked from time to time that Galena was to be found in Coal at Matlock in Derbyshire, and I have had a specimen sent me from thence, but it was so full of a decomposing Pyrites that it fell to pieces.

Lady Aylesford, whose ingenuity is well known, and who has a fine collection of drawings of nearly all the English plants, made by her own hand, was so kind as to exert herself, when in the country last autumn, and procure for me some very curious minerals from the Coventry; among which was the specimen here represented. This is not only rare from being among Coal, but for being in this curious hæmatitic form, a form which has not yet been noticed in Galena, and which will help more perfectly to show the nature of the substances that have a regular primitive crystal, passing into, or placing themselves in, a rounding figure.

The present specimen is radiating from a centre, forming circular and hæmisphærical segments, much resembling Hæmatitic Iron Ore—tab. 56.

This substance is evidently formed of cubes, and has assumed this particular shape from certain circumstances; and settling from its solvent with perfect preservation of its nuclei, which are very clear upon a careful examination. Although very minute, they are distinct cubes: and as any form made up of perfect cubes with level sides would, in forming a radiating figure, be loose in its texture, unless well closed with others in the interstices; so this, so loosely formed in that particular, is very useful to us to determine other facts of the like nature. The left hand figure is of two nuclei—and the right hand figure shows the manner of its accumulation, and will be useful in analogy.