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Bakerite (a new borosilicate of calcium) and Howlite from California

Published online by Cambridge University Press:  14 March 2018

W. B. Giles
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Extract

The new mineral to be described occurs as veins and as nodules of considerable size in the mines of the Borax Consolidated Company, Limited, situated in the Mohave Desert, sixteen miles north-east of Daggett in San Bernardino County, California. The white, amorphous masses resemble in appearance unglazed porcelain or fine white marble. Sometimes the mineral has a faint tinge of a sea-green colour. Its hardness is about 41/2 and specific gravity 2.73. Up to the present time no specimens showing any signs of crystallization have been noticed. In external appearance the mineral shows a striking resemblance to the pandermite of Sultan Tchair in Asia Minor, and it may be here noted that this amorphous variety of calcium borate occurs also in the Californian mines.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 13 , Issue 62 , December 1903 , pp. 353 - 355
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1903

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References

Note

1 Specimens of ‘bakerite’ presented by Mr. Giles to the British Museum appear to be perfectly homogeneous, except in one piece, which is intermixed with a little calcite. The microscopical examination of several fragments crushed in oil and of a thin section showed the material to have an extremely minute spherulitic structure and to be feebly birefringent. There was nothing suggestive of a mixture of minerals. On the other hand, the specific gravity of several small fragments from two specimens (differing somewhat in compactness and hardness) varied between about 2.7 and 2.93 (as determined in methylene iodide with indicators of calcite and aragonite).—L. J. Spencer.