Quartz-Jasper Enlarge
Feb. 1. 1805. Publiſhed by Ja.s Sowerby. London.
British Mineralogy
CLVII
Silex Quartzum; var. Jaspis

Quartz-Jasper

  • Class 2. Earths.
  • Order 1. Homogeneous.
  • Gen. 4. Silex.
  • Spec. 1. Pure.
  • Div. 3. Amorphous.
  • Syn.
    • Quartz-Jaspe. Haüy, 2. 435.
    • Gemeiner Jaspis. Emmerl. 1. 243.
    • Jasper. Kirw. 1. 309.

Some Jasper has the appearance of a ribband, and is called Ribband or Band Jasper. Either term is intelligible, and may answer the purpose well enough as to this part of the character, although it may with much propriety be called Stratified. Jasper is nearly allied to flint approaching hornstone, having rather a horny appearance. It is an impure amorphous Quartz, somewhat altered by a mixture of Argilla*. Its fracture is smooth, conchoidal or bluntish, splintery, very little translucent at the edges. It is rather tougher but scarcely harder than flint. It occurs in many varieties, and is often marked with darker and lighter stripes, but seldom very bright. Dull green is perhaps most frequent. The present figure exhibits a very distinct neatly striped vein in part of a variegated rock composed of Quartz, &c., and there are small threads in little veins passing irregularly from it. It was picked up on the coast of Airshire, and is in the possession of my friend Mr. Laing of Edinburgh.

I have pieces of large masses of Jasper striped or coloured nearly in the same way, from the shores of Scotland. Jasper was formerly much used for large trinkets, &c., as it takes a good polish.

  • * Porcelain Jasper is said to contain:
    95.216
    Silica 60.75
    Argilla 27.25
    Magnesia 3.00
    Oxide of Iron 2.50
    Potash 3.66
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