micropegmatite

Encyclopedia

micropegmatite

quartz and alkali feldspar intergrowth so fine that it can be resolved only under the microscope; it is otherwise indistinguishable from the coarser intergrowths known as graphic granite. The quartz-feldspar interfaces are planar, and the quartz areas tend to be triangular in cross section. These patches of quartz are in parallel optical orientation, and it was long supposed that they were actually continuous, either above or below the plane of observation; a detailed study of the coarser intergrowths common in many pegmatites indicated, however, that the various quartz patches usually are separate individuals. Both the angular (runic, or letterlike) character of the quartz areas and their optical parallelism are evidently crystallographic responses to growth conditions

Learn more about micropegmatite with a free trial on Britannica.com.

Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source
Explore Dictionary.com
Previous Definition: micropayment
Next Definition: micropenis
Words Near: micropegmatite
More from Thesaurus.com
Synonyms and Antonyms for micropegmatite
More from Reference.com
Search for articles containing micropegmatite
More from Dictionary.com Translator
Dictionary.com Word FAQs

Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.

Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature