The size and beauty of the specimens, and the abundance of this mineral near Shawnee Town, (provided there is no mistake in the case) clearly entitle this to be considered as the most interesting American locality of this beautiful mineral. Measures have been taken to investigate the subject more fully, and to obtain a supply of specimens.
Quartz crystals appear to abound at the same place, besides various other minerals.
Art. IV. Carbonate of Magnesia, and very uncommon Amianthus.
Art. IV. Carbonate of Magnesia, and very uncommon Amianthus, discovered near New-York.—Extract of a Letter from Mr. James Pierce to the Editor.
New-York, May 18, 1818.
DEAR SIR,
I forward you specimens of straw and rose-coloured amianthus I recently met with on Staten-Island, which I detached, in strips, from a rock; it not appearing, as is usual, in veins. It breaks up like flax, and may be spun and wove without the aid of moisture; and in respect to tenacity, flexibility, and length of fibre, it may be considered the best found in this country, and perhaps equal to any hitherto discovered. Staten-Island exhibits many minerals worthy of examination. I subjoin, as requested, the following geological description, &c.
Hoboken, where I discovered native carbonate of magnesia, is situated opposite the city of New-York, on the western or New-Jersey bank of the Hudson. It is a primitive, insulated elevation, with a nucleus of serpentine; the ground gradually descends in every direction except on the river side, where mural precipices of serpentine rock are observed, extending about 100 rods parallel with the water, and elevated from 60 to 100 feet above its level. The carbonate of magnesia I found in horizontal veins of nearly two inches in breadth, and of unknown depth, in a midway region of this serpentine ledge; I extracted a considerable quantity with a spoon. When first taken out it was soft, white, and very slightly adhesive, from a little moisture; but, when dry, fell to powder without friction. The nature of the mineral I immediately conjectured, and treated it with diluted sulphuric acid, in which it entirely dissolved with effervescence, forming a bitter fluid, and leaving no sediment. Upon evaporation, well-defined crystals of Epsom salts were formed. It differs little from the manufactured carbonate of magnesia of the shops; but is rather a super than a sub-carbonate. It has been analyzed by Professor Mitchill, who found it exclusively composed of magnesia and carbonic acid. Carbonates of magnesia, hitherto discovered, have been, I believe, found impure, and in a state of rock, requiring chemical process to render them serviceable; this is, perhaps, fit for immediate use. When I first mentioned the discovery to mineralogists, they were incredulous, supposing it did not natively exist in this state, but I convinced them by uniting it with sulphuric acid.