Aplome Enlarge
[Undated]
Exotic Mineralogy
LXXXII
Silex Aploma

Aplome

  • 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:

Silex 40   
Alumine 20   
Lime 14.5
Oxyde of Iron 14.5
Oxyde of Manganese 2   
Ferruginous Silex 2   
Loss by calcination 2   
Loss 5   
100.0
  • * When I completed British Mineralogy I had not ascertained this fact.
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