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Gem identification is basically a process of elimination. Gemstones of similar color undergo non-destructive optical testing until there is only one possible identity. Any single test is nearly always only indicative. For example: The specific gravity of ruby is 4.00, glass is 3.15–4.20, and cubic zirconia is 5.6–5.9 . So one can easily ...
Rhodolite garnets appear as transparent red-pink-purplish gemstones, including all the different colour shades between violet and red. The colors from different rhodolite sources may vary from a lavender pink to raspberry rose or raspberry red and from purplish-violet (grape) to purplish red.
The mineral is also referred to as lavulite, luvulite, and royal azel by gem and mineral collectors. [3] In Japan, sugilite is found as yellowish-white to colourless, and is not good for jewellery. [6] Sugilite on Matrix, Wessels Mine in Northern Cape Province, South Africa, size: 2.4 × 2.1 × 1.2 cm Sugilite owl and mouse, height 9 cm (3.5 in)
Specific gravity: 3.95–3.97: ... It is sometimes used as a gemstone. [12] Celestine from the Machow Mine, Poland ... Toggle the table of contents.
Refractive index readings of faceted gems can range around α = 1.651, β = 1.668, and γ = 1.689, with a biaxial positive birefringence of 0.037–0.038. With decreasing magnesium and increasing iron concentration, the specific gravity, color darkness and refractive indices increase, and the β index shifts toward the γ index.
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]
It was shown many years ago, by Sir Arthur Herbert Church, that many gemstones, especially engraved gems (commonly regarded as zircon), were actually hessonite. The difference is readily detected by the specific gravity, that of hessonite being 3.64 to 3.69, while that of zircon
It has a Mohs hardness of 4.5 to 5 and a specific gravity of 2.7 to 2.9. A highly sought-after variety known as larimar, is a pale to sky blue. There is also a whitish form of the mineral from Alaska that is sometimes marketed as 'Alaska jade'.