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Specific gravity: 3.60–3.61: Optical properties: ... it is the only gemstone to have been initially identified from a faceted stone. ... Toggle the table of contents.
Gemstones are basically categorized based on their crystal structure, specific gravity, refractive index, and other optical properties, such as pleochroism. The physical property of "hardness" is defined by the irregular Mohs scale of mineral hardness. Gemologists study these factors while valuing or appraising cut and polished gemstones.
It has a Mohs hardness of 5.5–6.5 and a specific gravity of 2.75–2.80. It is mostly translucent. It is mostly translucent. Sugilite was first described in 1944 by the Japanese petrologist Ken-ichi Sugi (1901–1948) for an occurrence on Iwagi Islet, Japan , where it is found in an aegirine syenite intrusive stock .
Like ballas diamond, carbonado lacks cleavage planes and its specific gravity varies widely from 2.9 to 3.5. Bort diamonds, found in Brazil, Venezuela, and Guyana, are the most common type of industrial-grade diamond. They are also polycrystalline and often poorly crystallized; they are translucent and cleave easily. [8]
Aquamarine is a fairly common gemstone, [6] rendering it more accessible for purchase, compared to other gems in the beryl family. [7] Overall, its value is determined by weight, color, [5] cut, and clarity. [8] It is transparent to translucent and possesses a hexagonal crystal system. [9]
The specific gravity of bytownite varies between 2.74 and 2.75. The refractive indices ranges are nα=1.563 – 1.572, nβ=1.568 – 1.578, and nγ=1.573 – 1.583. Precise determination of these two properties with chemical, X-ray diffraction, or petrographic analysis are required for identification.
Antigorite has a specific gravity of 2.5–2.6. The monoclinic crystals show micaceous cleavage , a distinguished property of phyllosilicates, and fuse with difficulty. [ 10 ] Serpentinite rocks that consist of mostly antigorite are commonly mylonites .
Jadeite is a pyroxene mineral with composition Na Al Si 2 O 6.It is hard (Mohs hardness of about 6.5 to 7.0), very tough, and dense, with a specific gravity of about 3.4.It is found in a wide range of colors, but is most often found in shades of green or white.