Chabasie

This species of Zeolite (formerly mentioned as found at Oberstein in Germany) is now figured with permission from a specimen in the cabinet of the Royal Institution, which H. Davy, esq. procured from Portrush in Ireland. It is in a hollow of a coarsish Siliceous Basalt, and is the primitive form, which differs little more than three degrees from the cube, being 931/2° at the obtuse summit. The crystals form more or less crowded groups in the hollows of the rock, and are irregularly-sized and placed. In their lustre they have lightish illinitions, that give them a Hawed appearance: they are nearly white and shining. It is sufficiently hard to scratch glass. Spec. Grav. 2.7176. It melts before the blow-pipe into a white spongy mass.

This specimen is very valuable, on account of the crystals of Chabasie being very perfect; and it has the inverse Carbonate of Lime in the hollow, very distinctly placed, and of a larger size and yellowish colour, which, not betraying in the least the effect of tire, may help in geological inquiries as to the dispute regarding Basaltic formations.