Browse Items (1651 total)

Dense

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Gneiss from the Bethlehem Gneiss series. Thin section contains biotite, plagioclase, alkali feldspar, and quartz. Hand sample shows slight discoloration (orange tinge) from weathering of an iron oxide, a high concentration of biotite, quartz, and…

Gneiss from the Bethlehem Gneiss series. Thin section contains plagioclase, alkali feldspar, biotite, quartz, and muscovite. Hand sample contains feldspars, quartz, and micas.

Gneiss from the Bethlehem Gneiss series. Coarser grained. Thin section contains biotite, muscovite, quartz, plagioclase, and alkali feldspar. Hand sample is coarser than NH-3 and contains quartz, feldspars, and micas. From the same locality as NH-4.

Gneiss from the Bethlehem Gneiss series. Thin section contains biotite, muscovite, quartz, and plagioclase. Hand sample is finer grained than NH-3 and contains feldspars, quartz, and micas. From the same locality as NH-3.

Gneiss from the Bethlehem Gneiss series. Thin section contains quartz, biotite, plagioclase, and muscovite. Hand sample is a leucocratic facies and contains quartz, feldspars, and micas.

Described as a "banded injection gneiss".

Example of the Dakin Hill Member. Porphyroblastic gneiss.

Synkinematic deformed gneiss w/ augen-like feldspar ribbons

cordierite-bearing

coarse-grained

Fenitized Gneiss. Gneiss discovered in direct contact with pyroxenite in prospect trench on ridge, about 500 ft. west of PH-1.. .

OCR PDF of supplemental information for the Grand Canyon collection.

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Granite from the Concord Granite series. Thin section contains plagioclase, alkali feldspar, biotite, quartz, and muscovite. Hand sample shows feldspars, quartz, and micas.

Hand Sample: Holocystalline, phaneritic, medim-grained granitoid with subhedral grains of smoky quartz, plagioclase feldspar, potassium feldspar, and biotite. Weathering to red-yellow on some surfaces.

coarse grained, porphyritic