Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/89



V. Memoir on the Laumonite. By M., F.R. & L.S. &c. Foreign Secretary of the Geological Society.

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[Translated from the original French Manuscript.]

substance, which has been long known under the name of efflorescent zeolite, has been termed Laumonite by Werner, in honour of M. Gillet de Laumont, to whom we are indebted for our first knowledge of it, as well as for many other important contributions to the science of mineralogy.

The former name of this mineral (efflorescent zeolite) was given to it, in consequence of the property it has of not being able to bear, even for a short period, exposure to the air without undergoing disintegration and finally falling into powder; and the opinion most generally entertained with respect to it was, that it belonged to the species of mesotype. It is however altogether different from that substance, nor does it belong to any of the numerous series of zeolitic minerals, which have hitherto been made known to us.

Highly calculated however as this substance is to excite the interest and the curiosity of the mineralogist, we have as yet had but very slight and imperfect descriptions of it. The author who has spoken of it most in detail is the Abbé Haüy.