from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A lustrous yellow, green, or black mineral, Ca2(Al, Fe)3(SiO4)3OH, commonly found in metamorphic rock.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of a class of mixed calcium iron aluminium sorosilicates found in metamorphic rocks
from the GNU version of the Collaborative International Dictionary of English
- n. A mineral, commonly of a yellowish green (pistachio) color, occurring granular, massive, columnar, and in monoclinic crystals. It is a silicate of alumina, lime, and oxide of iron, or manganese.
from The Century Dictionary and Cyclopedia
- n. A common mineral, occurring in prismatic crystals belonging to the monoclinic system, also massive, generally of a pistachio-green color and of a vitreous luster.
The feldspar is decomposed with the resulting formation of epidote, which is quite prominent.
Here is nobly born quartz living with a green mineral, called epidote; and they are immense friends.
Kata Tjuta, covering about 3,500 ha, comprises 36 steep-sided rock domes of gently dipping Mount Currie conglomerate consisting of phenocrysts of fine grained acid and basic rocks, granite and gneiss in an epidote rich matrix.
Basically, a process called metamorphism caused the basalts in Shenandoah to recrystallize with new minerals, such as chlorite, epidote, and albite, which help give the rocks their greenish hue.
Plagioclase remains a stable phase within the rock, though the mafic minerals have been altered primarily to chlorite + epidote.
The rarer stones, sphene and epidote, likewise exhibit this property markedly.
The summit of Crystal Head is of flat tabular form; and the sides, which are both steep and rugged, are covered with stunted trees and high grass, now quite dry: the geology of this part is principally of siliceous sandstone; and on the beach we found large detached water-worn masses of the same rock, incrusted with quartz and epidote in a crystallized state.
The wall rocks have undergone a "propylitic" alteration, with development of chlorite, epidote, and probably sericite, much as at Butte.
A fine grained compact gray rock, of aggregate structure, consisting chiefly of quartz, plagioclase and biotite, and the alteration products epidote and sericite.
Plagioclase, microcline and quartz are the predominating minerals, while biotite, titanite, epidote, apatite, zircon and garnet are present in smaller quantities.