Mesotype Enlarge
June 1. 1808. Publish’d by Ja.s Sowerby London.
British Mineralogy
CCLXVI
Silex Mesotypus

Mesotype

  • Class 2. Earths.
  • Order 1. Homogeneous.
  • Gen. Silex.
  • Spec.
  • Div. Crystallized.
  • Syn.
    • Zeolithes figurâ determinatâ crystallizatus. Waller. 1. 328.
    • Zeolithes Cronst. 108–112.
    • Zéolithe en aiguilles prismatiques ou pyramidales. De Lisle, 2. 41.
    • Argile unie à la terre silicieuse, faisant la moitié du poids, et quelquefois davantage, et à un peu de chaux. Zéolithe. Sciagr. 1. 301.
    • Zeolith. Emmerl. 1. 199. Wern. 1. 265.
    • Zeolite. Kirw. 1. 278.
    • La Zéolithe. Brochant, 1. 298.
    • Mesotype. Haüy, 3. 151.

The upper fine specimen from Raghlin in Scotland is preserved in the collection of G. B. Greenough, Esq., and is so beautiful as almost to surpass representation. The crystals are thinner and smaller than mine, but longer and very numerous, and their numbers give an idea of their being merely spiculæ; but being magnified they may be seen to have the same formation as in the larger ones.

The lower specimen came from Cave Hill near Belfast, and, like one of Mr. Grecnough’s, has almost all the ends broken away; which perhaps often happens, as I have seen many so, by their running in opposite directions against each other, which they frequently do; and in this and other instances the circumstance becomes interesting, as the inside reflects a transparent shadow owing to a small opacity on the outside, which seems natural to it, and on viewing the ends, gives them a rather singular and new appearance, somewhat resembling Chiastolite.—See tab. 116, right hand geometrical figure.

Is not the Nadelstein, Needle-stone, Needle-zeolite of Werner, the same with this substance? It is found in Iceland and Lower Brittany.

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