Primitive Carbonate of Lime, var

This curious crystal is sometimes found at Castle-Town in Derbyshire. its gangue is generally a bituminous limestone. it is a little milky on the outside, and roughish; those edges excepted which are rounded: see the left-hand figure. The right-hand figure has broad faces leading to the equiaxed crystal, which faces are as it were polished, and in the middle is a longitudinal line showing the edge of the nucleus, consequently the laminæ of superposition: see the upper part of the right-hand figure. There are also rough faces leading towards the metastatic crystal: see the lower part of the right-hand figure. As I had but indifferent specimens myself, I borrowed the specimen here figured of Mr. Richard Phillips, thinking it well worth noticing. The little black spots are drops of mineral pitch, which mostly accompany these varities. They generally have been termed primitive crystals, without further consideration. In an arranged collection they may be placed near to the primitive.