Gemstones with RI 1.555

7 gemstones have a refractive index range that includes 1.555. 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
Charoite1.550 – 1.5592.54 – 2.68MonoclinicAGG
Sunstone1.537 – 1.5722.62 – 2.65TriclinicDR_B-
Scapolite1.540 – 1.5722.50 – 2.74TetragonalDR_U-
Chrysocolla1.460 – 1.6302.00 – 2.40AmorphousAGG
Coral1.486 – 1.6582.60 – 2.70AggregateAGG
Lapis Lazuli1.500 – 1.6702.70 – 2.90AggregateAGG
Pearl1.520 – 1.6902.60 – 2.85AggregateAGG
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