132. SERPENTINE is a stone which, when polished, has a near resemblance to marble, is of dark green colour, or reddish; variously streaked, and spotted with lighter green, red, brown, and yellow.
It is found in beds, and in a massive state; is translucent at the edges; and, when pounded, the powder feels soapy to the touch.
There are few stones likely to prove more valuable in ornamental architecture, both for beauty and durability, than this. It admits of an excellent polish, which is not easily injured by the effects of air or water. It is also too hard to suffer the same inconveniences of being scratched or broken as marble; and its colours are stated to be indestructible. And such is the size of many of the blocks of serpentine, that columns of almost any dimensions may be wrought out of them.
Of the serpentine obtained from the Island of Anglesea, and lately known by the name of Mona marble, a great proportion was sent to London by Messrs. Bullock and Co. who, until the death of Mr. Bullock, had a large warehouse and polishing rooms for it in Oxford-street. The prevailing colours of this stone are red and green. The quarries were worked by them to considerable extent. They manufactured it into chimney pieces, slabs, columns, and other articles; and its great beauty, and its excellence, in many respects, over the generality of marbles, will recommend it strongly to the public notice.
The chief places in which serpentine has hitherto been found are near Bareuth, and Zöblitz, in Saxony; in some districts of Cornwall; about six miles west of the Paris copper mine, in the island of Anglesea; at Portsoy, in Bamffshire, and other parts of Scotland; and at Cloghan Lee, in the county of Donegal, Ireland.
At Zöblitz there are some extensive manufactories, in which serpentine is made into vessels and ornaments of various shapes, that are carried for sale over nearly all parts of Germany. Several hundred persons are there employed in the working of this stone.
The name of serpentine is derived from some of the varieties appearing coloured and spotted like a serpent’s skin. This stone, when found intermixed with primitive limestone, or crystalline white marble, differs in no respect from the celebrated verde antique marble ([149]).
133. POTSTONE, or LAPIS OLLARIS, is a greenish grey stone, unctuous to the touchy and so soft when first taken from the quarry as to yield to the pressure of the nail, yet not easily broken.
It is found in a massive state.
In consequence of the softness and tenacity of this stone, it can be turned upon a lathe, and otherwise cut and wrought with great ease. Hence, in Egypt, Lombardy, Norway, and other countries where it is found, it is formed into various kinds of culinary vessels and lamps, which harden in drying, and are capable of withstanding the strongest action of fire. Vessels of this description were known to the ancients; and are particularly mentioned by Pliny, the Roman naturalist, who speaks of some that were highly wrought being very valuable.