Amphibolite
cummingtonite-poor, brownish-green hornblende dominated
Western Minerals, Inc.
WCM-4
Amphibolite
1980
Western Minerals, Inc.
LT-16
Amphibolite
Sample contains porphyroblasts of poikilitic hornblende. Thought to represent Na-rich volcanic units.
1980
Western Minerals, Inc.
LT-3
Amphibolite
Rock Sample: <br />The color is a shiny dark grey with a bluish tint. Some parts of the sample are a more dark turquoise. Some faces are lighter and or darker than other faces. There is also a face with a brownish color and another face with a tannish color. The majority of the sample feels silty/sandy but there is one face that feels waxy. There are coarse grained blue-green phenocrysts, ranging in size of (2-8mm). Some of the phenocrysts are white linear phenocrysts (≤10mm in length). The matrix is apharitic. The sample experienced minor chemical weathering with some orange to brown blotches. This may have been due to oxidation. Some erosion took place on the sample, creating crater-like hole on the sides of the sample.<br /><br />Thin Section:<br />PPL. Abundant well-rounded hornblende crystals. Some of the hornblende cryststals are fairly large. The matrix has a flow-like fabric.<br />Hornblende: 50% <br />Plagioclase:30%<br />Quartz: 15%<br />Epidote:5%<br /><span>Magnification at 4x/0.10</span>
1969
Western Minerals, Inc.
TMJ-11
Amphibolite
Rock Sample:
The sample is very dark grey with light grey foliations.
The sample displays thin layering, some areas of chemical weathering, and microfoliations. It is aphanitic. There is quartz- like residue on the outside of the sample. It has a smooth feel throughout.
-Hardness = 5-6
-Streak = dark grey
Thin Section:
You can see very fine crystals within the thin section under the microscope. There is also a irregularly-shaped fracture within a quartz crystal. The sample is hypocrystalline, fine to medium sized glass crystals that flow with the rest of the minerals. A lot of the quartz is intergrown within augite crystals.
-Quartz (75%)
-Augite (20%)
-Plagioclase (5%)
-Magnification at 4x/0.10
1969
Western Minerals, Inc.
TMJ-09