Browse Items (1651 total)

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A highly graphitic slate in the Walloomsac slates. Contains pyrite. This rock also contains biotite, chlorite, muscovite, quartz, ilmenite, and pyrite.

The thin section shows large biotite grains, and chlorite muscovite, and quartz. Fluid…

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

Rock Sample:
The sample color is mainly light grey to white. There is a lime green layer as well as some dark grey and brown groupings. It is pegmatic and experiences non-congruent foliation and Y-shaped fractures. There are dark brown to orange…

from large sill

quartz monzonite facies

porphyroblastic

from satalitic pluton

darker than average facies

migmatitic with many feldspar strings and diklets

somewhat more leucocratic than normal

somewhat foliated

basic

medium grained, medium gray w/ pinkish tint

Hand Sample: Holocrystalline, medium-grained phaneritic granite with smoky quartz, potassium feldspar, and biotite