Browse Items (1651 total)

Contains orthoclase, ligoclase, and quartz phenocrysts and has alterations of kaolinite, sericite, and epidote

Biotite and feldspar are aligned, giving the rock a texture like porphyroblastic gneiss, some feldpsar has been altered to sericite, and some larger feldspar crystals are fractured

Biotite forms lineation in some hand specimens, much of the quartz and feldspar is fractured

Quartz and feldspar exhibit fracturing

Fedlspar and quartz exhibit fracturing

Extensively used in highway construction

Quatz appears strained, microcline is altered to muscovite and sericite, biotite is altered to chlorite

Quartz and feldpsar grains are closely interlocked and grains appear to be shattered

Exhibits a runic texture, the kind that is found in feldspar mining operations (undesirable due to high amount of quartz)

Biotite is variable in amount, but it is always evenly distributed

More quartz than sample 12

Sillimanite has been partly psuedomorphed

Some chlorite

Sulfur-rich

Grade bedded layers of pelitic bands and thin sandstones

Garnets and chlorite in pelitic bands

Moslty conglomerates, but partly staurolite rimmed with muscovite

Some remnants of andalusite

Staurolite rimmed with muscovite