Refractive Index	Mineral	Birefringence
from various sources	no guarantee	from various sources
1.701 - 1.706	Serendibite	0.005
1.702 - 1.750	Diaspore	0.047 - 0.050
1.706 - 1.730	Nambulite	0.023
1.708 - 1.735	Spinel	0.000
1.710 - 1.735	Kyanite	0.012 - 0.017
1.711 - 1.752	Rhodonite	0.011 - 0.014
1.712 - 1.726	Johachidolite	0.008 - 0.014
1.714 - 1.723	Sapphirine	0.006 - 0.007
1.715 - 1.797	Epidote	0.012 - 0.049
1.717 - 1.730	Taaffeite	0.00475
1.717 - 1.739	Musgravite	0.004 - 0.005
1.717 - 1.818	Bastnaesite	0.101
1.719 - 1.733	Bromellite	0.028
1.720 - 1.746	Hodgkinsonite	0.026
1.720 - 1.827	Xenotime-(Y)	0.095
1.720 - 1.848	Azurite	0.108 - 0.110
1.726 - 1.764	Pyroxmangite	0.016 - 0.020
1.727 - 1.883	Ilvaite	0.156
1.730 - 1.760	Grossular	0.000
1.730 - 1.766	Pyrope	0.000
1.730 - 1.800	Gahnospinel	0.000
1.730 - 1.829	Piemontite	0.025 - 0.076
1.732 - 1.744	Chambersite	0.012
1.735 - 1.744	Tsavorite	0.000
1.736 - 1.762	Staurolite	0.009 - 0.015
1.738 - 1.816	Scorodite	0.027 - 0.036
1.742 - 1.745	Genthelvite	0.000
1.742 - 1.748	Hessonite	0.000
1.745 - 1.759	Alexandrite	0.008 - 0.010
1.745 - 1.760	Rhodolite	0.000
1.750 - 1.780	Austinite	0.024
1.757 - 1.779	Ruby	0.008
1.757 - 1.779	Sapphire	0.008
1.757 - 1.804	Benitoite	0.046 - 0.047
1.760 - 1.830	Almandine	0.000
1.774 - 1.849	Monazite-(Ce)	0.049 - 0.052
1.777 - 2.025	Zircon	0.047 - 0.055
1.780	Gadolinite	0.050
1.780 - 1.810	Mandarin Garnet	0.000
1.787 - 1.816	Painite	0.027 - 0.029
1.790 - 1.807	Hibonite	?
1.790 - 1.818	Gahnite	0.000
1.790 - 1.820	Spessartine	0.000
1.804 - 2.079	Cerussite	0.271 - 0.273
1.810 - 1.920	Bahianite	0.110
1.850 - 1.899	Topazolite	0.000
1.860 - 1.870	Uvarovite	0.000
1.860 - 1.950	Andradite	0.000
1.878 - 1.895	Anglesite	0.017
1.880 - 1.889	Demantoid	0.000
1.885 - 2.034	Titanite / Sphene	0.100 - 0.192
1.890 - 1.940	Melanite	0.000
1.918 - 1.936	Scheelite	0.016 - 0.017
1.974 - 1.984	Powellite	0.010
1.976 - 2.045	Simpsonite	0.020
1.997 - 2.098	Cassiterite	0.103