Amphibole Mineral
Amphibole is a group of silicate minerals, composed of varying amounts of silicon, oxygen, aluminum, iron, magnesium, calcium, sodium, and other elements. The most common amphibole minerals are hornblende and actinolite.
Physical properties:
Color: Amphibole can vary in color from black, green, brown, gray, to white.
Luster: Amphibole can have a vitreous, dull, or metallic luster.
Transparency: Amphibole can be transparent to opaque.
Crystal habit: Amphibole typically forms as prismatic or elongated crystals, sometimes with a square or rectangular cross-section.
Hardness: Amphibole has a Mohs hardness of 5-6.
Specific gravity: Amphibole has a specific gravity of 2.9-3.5.
Cleavage: Amphibole has two directions of perfect cleavage at about 56 and 124 degrees.
Fracture: Amphibole has a conchoidal to uneven fracture.
Magnetic properties: Amphibole is not magnetic.
Thermal conductivity: Amphibole has a low thermal conductivity.
Optical properties:
Refractive index: Amphibole has a refractive index of 1.62-1.68.
Optic sign: Amphibole is biaxial negative
Dispersion: Amphibole has a moderate dispersion.
Pleochroism: Amphibole exhibits strong pleochroism, with different colors appearing in different orientations.
Birefringence: Amphibole has a moderate birefringence of about 0.009.
Extinction: Amphibole has an extinction angle of about 20-30 degrees.
Interference colors: Amphibole typically exhibits first-order gray or yellow interference colors.
Relief: Amphibole has a moderate relief.
Optic axis: Amphibole has two optic axes.
Uses:
Amphibole is not a commonly used mineral, but it is sometimes used as a decorative stone in jewelry or as a specimen for collectors.
Amphibole is also a common mineral in metamorphic and igneous rocks, specifically in rocks like gabbro, basalt, and schist.
Amphibole is also used in the manufacture of ceramics, abrasives, and as a filler in paint and plastics.
In addition, amphiboles have been used in the past to study the geology of the earth's crust and it can also be used as a mineral indicator for certain geologic processes.
Please note that these properties can vary depending on the exact composition and impurities present in the mineral specimen.
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