Browse Items (1651 total)

Much of the plagioclase has been altered to epidote and sericite, hornblende occurs as long prismatic crystals arranged in sprays

Plagioclase altered to epidote and flaky sericite, rock has undergone slight metamorphism

Quarred for monumental stone, ophitic texture in thin section, minor amount of opaques

Ophitic texture in thin section, some opaques

Ophitic texture in thin section, some opaques

Ophitic texture in thin section, plagioclase exhibits some alteration to sericite

Shows considerable fracturing, thin section examination shows ophitic texture

Mostly plagioclase and biotite

Gabbro associated with syenite ring dike near Concord, North Carolina

Mostly quartz, oligoclase, and microcline

Chlorite, epidote, and mica are present as secondary minerals

Quartz and feldspar appear to be shattered

Some feldspar shows slight alteration

Contains sutured grain boundaries, conversion of hornblende to magnetite, and some fine-grained alteration products

Similiar in composition, texture, and shape to the Concord, North Carolina complex

Contains augite, amphibole, plagioclase, ziron, opaques, and a fine-grained alteration product (unknown)

Contains inclusions of relict gabbro

Quartz and feldspar phenocrysts, rounded diabase inclusions

Phenocrysts of lath shaped feldspars and beta quartz