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Hornblende has a hardness of 5–6, a specific gravity of 3.0 to 3.6, and is typically an opaque green, dark green, brown, or black color. It tends to form slender prismatic to bladed crystals, diamond-shaped in cross section, or is present as irregular grains or fibrous masses. [7] Its planes of cleavage intersect at 56° and 124° angles.
Amphibolite (/ æ m ˈ f ɪ b ə l aɪ t /) is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flaky) structure.
Hornblendite from Poland. Hornblendite is a plutonic rock consisting mainly of the amphibole hornblende. Hornblende-rich ultramafic rocks are rare and when hornblende is the dominant mineral phase they are classified as hornblendites with qualifiers such as garnet hornblendite identifying a second abundant contained mineral.
Amphibole ()Amphibole (/ ˈ æ m f ə b oʊ l / AM-fə-bohl) is a group of inosilicate minerals, forming prism or needlelike crystals, [1] composed of double chain SiO 4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.
The side of the diagram between calcite and sillimanite has a point added for anorthite (calcium feldspar), corresponding to an equal mixture (by mole percentage) of the two components. This forms pure anorthite. Likewise, points are added for clinopyroxene and garnet and the diagram is divided into subtriangles, as depicted in the accompanying ...
One of the most powerful online tools at your disposal is the sprawling Google Earth project, which allows you to use satellite imagery to view a three-dimensional representation of the planet ...
Purely pyroxene-bearing volcanic rocks are rare, restricted to spinifex-textured sills, lava tubes and thick flows in the Archaean greenstone belts.Here, the pyroxenite lavas are created by in-situ crystallisation and accumulation of pyroxene at the base of a lava flow, creating the distinctive spinifex texture, but also occasionally mesocumulate and orthocumulate segregations.
The fragments then formed Bennu and other "rubble pile" asteroids - loose amalgamations of rocky material rather than solid objects. Early in its history, some of the ice inside the parent body ...