Browse Items (1651 total)

Mica schist containing coarse (altered) andalusite crystals

Macroscopic: An andalusite, biotite schist with large and abundant garnet porphyroblasts. Low grade of metamorphism. Microscopic: Large andalusite and cordierite phenocrysts within very fine grained matrix. Thin section pictures in XPL unless…

Macroscopic: Andalusite, biotite, garnet, muscovite, chlorite schist. Heavily weathered exterior due to divets and altered nature. High abundance of foliated mica. Microscopic: The andalusite, biotite, and garnet are porphyroblastic with andalusite…

1:24000
comes with full-sized sheet detailing units and structure

1:24000
comes with full-sized sheet detailing units and structure

1:24000

1:24000

pre-batholith volcanic

Rock Sample:
The color is mainly blue and black. The sample is aphanitic and the cross section of the sample reveals very fined grained phenocrysts (~1mm in diameter). The colors of the phenocrysts range from white, blue, black, or green.
It has…

possibly crystal tuff

Ankaramites are dark porphyritic basalts that contain abundant pyroxene and olivine phenocrysts. Lesser amounts of biotite, and plagioclase may also be present.

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The specimen was collected from the Oregon Dome Massif. The Oregon Dome is similar in all respects to the anorthosites described and analyzed by Buddington (1939) for the Adirondack High Peaks region (Marcy Massif). Texturally, the present specimens…

Mined and marketed under the name "Aplite"

Fine-banded, most of the bands are several inches wide and alternate light-dark

Many have large dark mineral clusters

1:62500

1:62500