Medium Coarse Grained Adamellite
Hand Sample: Holocrystalline, phaneritic, fine-to-medium-grained quartz monzonite. Mineralogy includes large plagioclase laths up to 8mm in length, quartz, alkali feldspar, biotite. Very large crystals of a dark material up to 3cm in length. Weathering to dark yellowish black and brown. Very thin vein of dark material with thermal alteration on either side.
Thin Section, XPL: Euhedral medium-grained plagioclase crystals and subhedral medium-grained quartz crystals with smaller percentages of subhedral medium-grained diopside and fine-grained biotite crystals. quartz 60%, alkali 10%, biotite 30%
Western Minerals, Inc.
Is Part Of
St. Francois Mtns. Batholith, Missouri
Purchased from Western Minerals, Inc.
Number of Thin Sections