Stilbite

Stilbite is partly distinguished by the peculiar lustre of the surfaces of its lamina, resembling some sorts of Gypsum, such as tab. 233. which figure is from a specimen of a silver or satin like lustre, and partly talcose aspect; a character that it is scarcely possible to represent, but which is eminently conspicuous in the specimen I have here figured from Scotland. The crystals upon it are rectangular prisms, the faces of which are primitive; it is a rare form: the nucleus, according to Haüy is a very short prism, although the crystals generally assume an elongated one.