Gemstones with RI 1.750

14 gemstones have a refractive index range that includes 1.750. 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
Alexandrite1.746 – 1.7553.70 – 3.78OrthorhombicDR_B+
Cat's Eye Chrysoberyl1.746 – 1.7553.70 – 3.78OrthorhombicDR_B+
Chrysoberyl1.746 – 1.7553.70 – 3.78OrthorhombicDR_B+
Color-Change Garnet1.740 – 1.7653.65 – 3.80CubicSR
Grossular Garnet1.734 – 1.7593.57 – 3.73CubicSR
Hessonite Garnet1.730 – 1.7603.59 – 3.65CubicSR
Malaya / Umbalite Garnet1.730 – 1.7803.65 – 3.87CubicSR
Pyrope Garnet1.730 – 1.7603.62 – 3.87CubicSR
Rhodolite Garnet1.740 – 1.7703.74 – 3.94CubicSR
Tsavorite Garnet1.730 – 1.7603.59 – 3.65CubicSR
Rhodonite1.716 – 1.7523.57 – 3.76TriclinicDR_B+
Diaspore1.685 – 1.7523.30 – 3.39OrthorhombicDR_B+
Malachite1.655 – 1.9093.60 – 4.05MonoclinicDR_B-
Rhodochrosite1.600 – 1.8203.40 – 3.70TrigonalDR_U-
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