greisen

American  

[grahy-zuhn] / ˈgraɪ zən /

noun

1. a hydrothermally altered rock of granitic texture composed chiefly of quartz and mica, common in the tin mines of Europe.

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greisen British  

/ ˈɡraɪzən /

noun

1. a light-coloured metamorphic rock consisting mainly of quartz, white mica, and topaz formed by the pneumatolysis of granite

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Etymology

Origin of greisen

Borrowed into English from German around 1875–80

Example Sentences

The greisen bands are from 1 in. up to 2 ft. or more in thickness.

From Project Gutenberg

Cassiterite usually occurs as veins or impregnations in granitic rocks, and is especially associated with the quartz-mica rock called greisen.

From Project Gutenberg

The wall rocks are usually strongly altered and in part are replaced by some of the above minerals, forming coarse-grained rocks which are called "greisen."

From Project Gutenberg

The transition between the two rocks is perfectly gradual, a fact which shows that the greisen has been produced by alteration of the granite.

From Project Gutenberg

The latter is a pneumatolytic product consisting of quartz and tourmaline; it often contains white mica and thus passes by all stages into greisen.

From Project Gutenberg