from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A rare plagioclase feldspar with high calcium oxide content occurring in igneous rocks.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A plagioclase feldspar, the final member of the Albite-Anorthite solid solution series. Anorthite is very rare on Earth, but abundant in moon rocks. This is because Anorthite weathers rapidly to clay minerals under atmospheric conditions. Good crystals have been found in lava-digested limestone blocks erupted from Mount Vesuvius.
from the GNU version of the Collaborative International Dictionary of English
- n. A mineral of the feldspar family, commonly occurring in small glassy crystals, also a constituent of some igneous rocks. It is a lime feldspar. See feldspar.
from The Century Dictionary and Cyclopedia
- n. A triclinic lime feldspar, found in small transparent crystals on Mount Vesuvius, and existing also as a constituent of some rocks. See feldspar.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. rare plagioclastic feldspar occurring in many igneous rocks
Like labradorite and anorthite, it is a common constituent of basic igneous rocks, such as gabbro and basalt.
In chemical composition and in optical and other physical characters it is thus much nearer to the anorthite end of the series than to albite.
The name was afterwards applied by G. Tschermak to those plagioclase felspars which lie between labradorite and anorthite; and this has been generally adopted by petrologists.
The minerals anorthite, albite, and orthoclase named in this figure are all feldspars; sylvite and halite are chlorides of potash and soda.
This young scientist, too, cherished loving thoughts about Angelina, thoughts of a more earthly and volcanic tinge; certain definite projects which made him forget, at times, his preoccupation with biotite, perlite, magnetite, anorthite, and pyroxene.