Gemstones with RI 1.775

6 gemstones have a refractive index range that includes 1.775. Refractive index measures how much light bends when entering a gem — it's one of the most diagnostic properties for identification. Measured with a gemological refractometer.

← All RI Values

GemstoneRI RangeSG RangeCrystal SystemOptic Character
Benitoite1.757 – 1.8043.64 – 3.68HexagonalDR_U+
Malachite1.655 – 1.9093.60 – 4.05MonoclinicDR_B-
Malaya / Umbalite Garnet1.730 – 1.7803.65 – 3.87CubicSR
Almandine Garnet1.770 – 1.8303.93 – 4.30CubicSR
Star Garnet1.770 – 1.8303.93 – 4.30CubicSR
Rhodochrosite1.600 – 1.8203.40 – 3.70TrigonalDR_U-
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