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NOME XXVI. LIME-STONE, WITH ACTI
The beautiful rose-coloured marble of Tirey not only contains large crystals of siderite, sometimes an inch and a half in length, of a black or very dark green colour, bat numerous other crystals of a lighter green, which every candid observer would allow to be the same substance, with a slight diversity of colour. It seems now to be universally allowed by the most skilful mineralogists, that actinote is only a diversity of siderite, with a greater portion of magnesia, an earth which singularly affects the green colour. But this actinote must not be confounded with the epidote of Haüy, a mistake into which many writers have fallen, whereas the latter contains no magnesia, and a greater quantity of lime*. Under the epidote he ranks zoisite, so called from Baron Zois; and the scorza, or greenish sand, found near Muska, in Transylvania. The sahlite he ranks under pyroxene, or augite. These substances are mentioned because they have been supposed to have been found in the marble of Tirey, which sometimes also presents
See his Tableau comparatif, Paris, 1809. 8vo. notes 51, 55.
a substance resembling red garnets; or perhaps they are only altered by the gangart, and might be found upon analysis to correspond with those found in the lime-stone of the Pyrenees. Thus the singular appearance of the flint discovered at Menil Montant, near Paris, and which resembles pitch-stone, probably only arises from the soft and unctuous marl in which it is always found. This important observation may be said to have escaped all writers on mineralogy.
It is remarkable that marbles similar to that of Tirey occur in Scandinavia. A northern mineralogist, Mr. Neergard, observes that there are, in all Sweden and Norway, only two quarries of marble which are wrought *.
“ That of Fagernich, in Sweden, is situate between the two little towns of Norkiöping and Nykiöping, and about thirty leagues from Stockholm. It belongs at present to Mr. Eberstein of Norkiöping, and to Baron Unger, who purchased it from Count Gyllenberg for only 200,000 francs, on account of its bad condition. This marble, which is white, with veins of
green talc, the fracture brilliant, began to be wrought about a hundred and fifty years ago, in the reign
* Brard, Traité des pierres, Paris 1808, 8vo. ii. 444. VOL. II.
of Queen Christina. The space where it is found is about 2000 fathoms in length, but its breadth is inconsiderable. They make of it tombstones, slabs for tables, vases for butter, salt cellars, and mortars; and the sale of these different articles amounts annually to about 20,000 francs. There are magazines of it at Stockholm, at Gottenburg, at Carlskrona, and at Abo. The manufactory employs about twenty workmen, who receive each two livres ten sous (about two shillings) daily; and its position is fine and well adapted for working, as it is near the Baltic sea.
“ The marble-quarry of Gillebeck, in Norway, is seven leagues distant from Christiana ; but as the marble which it furnishes is saturated with a great quantity of pyrites, it generally becomes decomposed in a few years. The great church of Frederick, at Copenhagen, which is unfinished, is built with this marble. I have often seen some pretty tablets of it, which contained garnets, and a green substance called actinote.”
The Tirey marble seldom takes a fine polish.. Perhaps by a mill, or a steam-engine, and high friction with putty, this defect might be remedied. But granite itself seldom admits a perfect polish, owing, as in the Tirey marble, to the
different hardness of the ingredients. Besides, our artisans, only accustomed to soft marble, seldom possess the instruments necessary for hard substances; and a laudable change in the public taste can alone drive them from their routine.
NOME XXVII. MARBLE, WITH ASBESTOS.
This uncommon mixture is found in the Pyrenees, and, it is believed, in Sweden.
General THESE rocks, in which the substances
may be said to be chemically combined, form the most difficult province of the whole science, and might deserve a separate treatise, like the Cryptogamia of the Botanists. Siderous earth, for example, may be found so intimately and equally combined with the siliceous, that the rock