Anthracite, or Stone Coal
There are two principal varieties of Stone Coal; one that occurs in large beds or strata, connected in general with bituminous Coal, the bitumen of which being dissipated by some causes associated with the introduction of Whin Dykes through the strata, has left the Carbon in the form of Coak, of Plumbago, or of the bituminous Coal itself: the other variety occurs in small quantities in mineral veins traversing Gneiss, Mica Slate, and Transition Rocks: we have no means of tracing the origin of this variety from animal or vegetable substances, but it may possibly result from the decomposition of bitumen, such as is found in some of the copper veins of Cornwall: that it was once more bulky than at present is evident from the number of cracks that pervade it, and which are often filled with iron pyrites, or other foreign matter; to this variety the name Anthracite appears to have been originally attached: I do not know that it has been met with in any part of Great Britain. At Kongsberg, in Norway, it is found upon Quartz, accompanied with Carbonate of Lime, Fluor, native Silver, See. Bournon mentions a specimen from this place, in which the Anthracite is both pulverulent and in globules, as if it had run into that form. The mine at Kongsberg is said to be in Mica-slate. It is found also in Spain, Switzerland, the Hartz, and Schemnitz in Hungary.
The specimen figured is part of a vein of Iron-stone, containing much Quartz, crystallized in the hollows, which contain besides the Anthracite, specular Iron and Iron Pyrites. It is one of Prof. Strbmcyer's kind favors it was collected at Lerbacb, in the Hartz.