Red Mesotype and Red Zeolite Enlarge
JS July. 1. 1816
British Mineralogy
Silex Mesotypus

Red Mesotype and Red Zeolite

The colour of the variety of Mesotype exhibited in the upper figure has apparently misled, as it has long remained in several collections among uncertain species. It is formed in Amygdaloid, like the other Zeolites, and has lined the cavities, more or less accumulating or filling them up, or succeeded by Carbonate of Lime or some other substance. The specimen selected has earthy or nearly loose wacko outside; then commences the Mesotype which is conspicuous from its redder colour, and passes in stellated fibres into Carbonate of Lime, of the sort that exposes the diagonal fracture very distinctly, as happens in many Scotch specimens. 1 believe the outside of the rock or exposure to changes of weather makes them conspicuous, as they seldom extend far within. The lower specimen is nearly all Mesotype, the whiter as well as the coloured part, the strike passing either into the solid or perfectly relieved in hollows: it serves to illustrate and connect the above variety with the commoner white ones, tabs. 265 and 266.

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