How to use phenocryst in a sentence
In a basal flow in Moraine Park, the slaggy and compact phases show differences in phenocrysts as well as in groundmass.
Mount Rainier | VariousIn Moraine Park gray andesites also predominate, with both pyroxenes as phenocrysts, but here hypersthene is the more important.
Mount Rainier | VariousThe camptonites (called after Campton, New Hampshire) are dark brown, nearly black rocks often with large hornblende phenocrysts.
Of the darker phenocrysts, the pyroxenes are more abundant than the olivine or hornblende.
Mount Rainier | VariousMany dolerites are porphyritic and carry phenocrysts of olivine, augite and plagioclase felspar (or of one or more of these).
British Dictionary definitions for phenocryst
/ (ˈfiːnəˌkrɪst, ˈfɛn-) /
any of several large crystals that are embedded in a mass of smaller crystals in igneous rocks such as porphyry
Origin of phenocryst
1Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for phenocryst
[ fē′nə-krĭst′ ]
A large crystal that is surrounded by a finer-grained matrix in an igneous rock. Phenocrysts are usually the first crystals to form from a cooling magma, and therefore have sufficient room to grow to a large size. They are analogous to porphyroblasts in metamorphic rock.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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