Carbonate of Lime

The last plate showed the coalesced crystals yet distinctly marked with the remains of the usual column of Carbonate of Lime. The present specimen, not having this column on the diagonals of the rhomboidal faces, but at their acute angles, has so different an appearance, that it would be scarcely recognisable but to the more experienced. This specimen has rounding faces on all the edges; but on the terminal ones they are, as in the last, much the broadest; but they do not extend over the primitive faces, which are still distinct in the centre of each of the six sides, forming more or less of an elongated rhomboid. We may here count, thirty-six faces. The obtuse rounding ones passing round the six edges of the crystal, unite as it were two into one; and each is crossed by the outline of the primitive rhomb. The acute corner faces belonging to the column have signs of the faces that round a little in tab. 306. The whole is somewhat elongated, and accompanied by other irregular ones; and we cannot always see them in the best position to show the axis as might be desirable, and as in the outline below. There are a series of these crystals; but an attention to these two will probably make them less difficult to comprehend when we light on them.