- Syn. Aplome.
- Haüy Traité, IV. 336. Tabl. 58.
- Bournon’s Catal. 42. Aikin, 226.
This was first described as a species by Haüy: it bears a considerable resemblance to common Garnet, but is distinguished from it by striæ along the short diagonals of the faces of the rhomboidal dodecahedrons, in which it crystallizes: it has also an indistinct foliated structure parallel to the faces of a cube, with less lustre, and an inferior specific gravity. There are two principal varieties; one in small crystals of a more or less dull green or yellowish green colour, from the Bannat; the other in larger crystals of a brown colour, from Schwarzenberg in Saxony: this latter is the variety I have seleeted from the British Museum, as it exposes its characters best in a figure. I have also added a sketch from the British specimen mentioned by Bournon in his catalogue. I am informed by Mrs. Mawe, from whom the Count obtained it, that it was found in digging a well in some part of North Wales.* The crystals want the characteristic striæ; but this defect is supplied by truncations upon some of the solid angles, indicating the same primitive: the black substance in which they are imbedded is Oxide of Manganese.
Laugier gives us the following analysis:
|Oxyde of Iron||14.5|
|Oxyde of Manganese||2|
|Loss by calcination||2|
- * When I completed British Mineralogy I had not ascertained this fact.