Hyalite Enlarge
Exotic Mineralogy
Silex Hyalithus


  • Syn.
    • Hyalite. Kirw. 1, 296.
    • Quartz concrétionné (in part). Haüy II. 416. Tabl. 25.
    • Muller’s-glass and Lava glass, of many.
    • Hyalith of Werner.

This mineral has been long known, and yet many mineralogists are still wavering in their opinions respecting it; some considering it a variety of Quartz or Calcedony; others joining it with Fiorite, Zeolite, &c. but all with some hesitation: in its composition it approaches to Opal, but differs in lustre, form, and texture, so [illegible] at present, seems best to insulate it. Its resemblance to gum spread in masses [illegible] surfaces of the cavities of the Basalt in which it occurs, is so exact, in consequence of its great lustre, and the fine cracks that travel it, that if is only necessary in its description to [illegible] that its hardness is nearly equal to that of Quartz, and its form between botryoidal and mamillated. The upper figure represents a specimen from Frankfurt on the Mayn; the other one from Bohunitz, in Hungary; they are both in the collection at the British Museum. Bucholz gives us the following analysis:

Silex 92.    
Water 6.33
A trace of Argilla
Loss 1.67
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