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NATURAL HISTORY OF MAGNESIA.

MAGNESIA.

PART LXIV.

SECT. I.

NATURAL HISTORY OF MAGNESIA

This earth is not found pure in nature, but is obtained by artfrom some of its combinations. It gives a peculiar character tothe substances of which it forms a part. The stones which con-tain magnesia in considerable quantity, have generally a smoothand unctuous feel, a greenish cast, a fibrous or striated texture,and a silky lustre. Among them we may mention talc, steatite,serpentine, chlorite, aslestos, actynolite, jade or nephritic stone,laikulite, loracite, tsfc. It is likewise found neutralized withvarious acids. It has been discovered by Vauquelin, in severalsea-plants.*

PROPERTIES OF MAGNESIA.

Pure magnesia does not form with water an adhesive ductilemass. It is in the form of a very white spongy powder, soft

Ann. dc Chcmie. xvlii, 78.