from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A granitic rock composed chiefly of quartz and mica.

from The Century Dictionary.

  • noun A rock of the granitic family, having a crystalline-granular texture, and chiefly made up of quartz and mica.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Min.) A crystalline rock consisting of quarts and mica, common in the tin regions of Cornwall and Saxony.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun geology A highly altered granitic rock containing quartz and mica

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a granitic rock composed of quartz and mica


from The American Heritage® Dictionary of the English Language, 4th Edition

[German, from greissen, to split.]


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  • 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."

    The Economic Aspect of Geology 1915


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