Primitive crystallized Carbonate of Lime

Upper figures. We believe these small crystals represented on the piece of pyritaceous coaly substance, are the true nucleus or primitive crystal of carbonate of lime, having measured them as well as we could. It appears to be a rare thing at present to find them so perfect in Britain.

Those that are larger are either foreign or partaking of the pearly lustre belonging to the Sidero Calcite of Kiran, v. 1. 105. Chaux carbonatée, Haüy, v. 1. 175. The line of separation is hardly discernible.

Lower figures. The fractures in the mass afford an excellent help to discern these as little flat primitives; those detatched agreeing with the fractures of the flat mass. These, although perhaps not before noticed, may commonly be found in thin layers, or separate in the small partings in the Newcastle coals, from nearly pellucid to nearly opaque white, not unfrequently prismatically coloured, or coated with silvery or golden coloured pyrites, and may sometimes be found very beautiful. Wishing to make the subject familiar, I felt a pleasure in introducing a thing to easily procured.