Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/147

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Thus we find, that all those rocks which are geologically arranged with serpentine, contain in greater or less proportion, several substances quite foreign to it, and what is still less satisfactory, we find that the same rocks analysed by different chemists, frequently give very different results. I believe that upon full examination, we shall agree with the observation of Saussure, that substances of very dissimilar natures are often included in rocks which do not at all, or very slightly resemble them, although both may have been formed simultaneously; but that, in consequence of certain principles of affinity, the similar particles of the different materials suspended in the fluid, united and formed distinct rocks.

In considering the steatite, a mineral which still more frequently than the diallage and jade accompanies the serpentine, I shall adopt the same method I have pursued in treating of these last substances.

Steatite is found not only intimately combined with serpentine, but frequently in masses forming subordinate beds in that rock; such are the soap-rocks at the Lizard.

There is in the valley of Sesia Grande, about half a league to the north of Alagna, and consequently, at the foot of Mount Rosa, a bed of true potstone in the serpentine: It is so soft as to be worked upon the lathe, and dishes are made of it which are known in the country by the name of lavezzi. But I learned upon the spot, in 1806, that they had given over working the quarry, since it had been encumbered by the fall of an enormous block of serpentine. In the mountains of Chiavenna, and also in the valley of Chamouni, steatite, in scattered blocks is often met with, though, according to the observation of Saussure, less frequently on the side of the Alps than on. the side of Italy.

Estner suspects, that the beilstein (a variety of steatite) must form