Crystallized Carbonate of Lime

This, and the last figure, have nearly the same form of crystallization, and also in some parts the appearance of Carara marble more complete, with a very white surface. Among the substances concerned in this composition or decomposition we find Sulphuret of Iron neatly coating the crystals, which are more perfect than those in the former figure, few having the corroded or half coated appearance; and so accurately docs the Sulphuret of Iron fit upon most of them, that it could not have been discerned but that they were solid metallic crystals of Sulphuret of Iron, with a gold blued steel, or copper-coloured, appearance. These so complete coverings are very thin, and, when magnified, are found to be composed of minute bubbles, with the fine mammillated appearance of the bubbled fusion belonging to metals, although the effect of a fire to produce such a fusion would certainly have given opacity to the crystals covered with it, which the broken ones discover to be otherwise; that is, to be Carbonate of Lime.

I am obliged to my worthy and scientific friend the Rev. Dr. Jackson for presenting me with these remarkable specimens, from the Dimple mine near Matlock, which give a fine idea of the changes passing on, in darkness to us, although our excavations, when mining, may let in fresh agents to the veins or lodes, which may probably assist in them, and may sometimes, though unknowingly, be useful, or the contrary. It may, however, be worth a little attention, as in some instances it may be of great consequence.