Specific Gravity & Refractive Index

Reference the specific gravity and refractive index for over a dozen faceted gemstones with this chart.

Last edited: 8/27/2019
Specific Gravity & Refractive Index
Stone S.G. R.I.
Alexandrite 3.71–3.72 1.75–1.76
Amethyst 2.65 1.544–1.553
Ametrine 2.65 1.544–1.553
Aquamarine 2.68–2.90 1.577–1.583
Citrine 2.65 1.544–1.553
Chrome diopside 3.22–3.40 1.675–1.701
Diamond 3.515 2.417
Emerald 2.68–2.78 1.560–1.602
Garnet 4.05 1.79
Iolite 2.61 1.542–1.551
Opal, fire 2.15 1.37–1.45
Peridot 3.34 1.654–1.690
Quartz, smoky 2.65 1.544–1.553
Ruby 4.00 1.760–1.770
Sapphire 4.00 1.760–1.770
Tanzanite 3.35 1.692–1.700
Topaz 3.53 1.619–1.627
Tourmaline 3.06 1.624–1.644