Hornblende Enlarge
Feb 1 1813 published by Jas Sowerby London.
British Mineralogy
Silex fragilis


  • Class 2. Earths.
  • Ord. 1. Homogeneous.
  • Gen. 4. Silex.
  • Spec. . Fragilis.
  • Syn.
    • Amphibole. Haüy Tabl. 39. Traité, 3. 58.
    • Hornblende. Emmerl. 1. 323.
    • Basaltic Hornblende. Kirwan, 1. 219.

After waiting from the time of publishing tab. 328 to the present, I do apt find that there are better British specimens of Hornblende than the present, which is from the neighbourhood of Aberdeen. It is, however, very imperfectly crystallized, although the columnar form is recognizable. It is readily distinguished by its laminated structure and dark green or black colour: its laminæ are parallel to the sides of an oblique rhomboidal prism of 124° 34′, the terminal faces of which are inclined towards the obtuse edge of the prism at 104° 57′. The white part of this specimen is Feldspar, thus constituting a Greenstone, one of the Trap flocks of Werner; and from the largeness of its grains I suppose it to be one of the older varieties.

Analysis by Klaproth. By the same.
Silica 47    42     
Alumina 26    12     
Magnesia 2   
Lime 8    11     
Oxide of Iron 15    32     
Volatile Matter 0.5 Water 0.75
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