TABLE III
Reading edition
Refractive Indices of Gem-Stones[8]
Opal 1·454
Moonstone 1·53 1·54
Iolite 1·543 1·551
Quartz 1·544 1·553
Beryllonite 1·553 1·565
Beryl 1·578 1·585
Turquoise 1·61 1·65
Topaz 1·618 1·627
Andalusite 1·632 1·643
Tourmaline 1·626 1·651
Apatite 1·642 1·646
Phenakite 1·652 1·667
Euclase 1·651 1·670
Spodumene 1·660 1·675
Enstatite 1·665 1·674
Peridot 1·659 1·697
Axinite 1·674 1·684
Diopside 1·685 1·705
Idocrase 1·714 1·719
Spinel 1·726
Kyanite 1·72 1·73
Epidote 1·735 1·766
Garnet (Hessonite) 1·745
Chrysoberyl 1·746 1·753
Garnet (Pyrope) 1·755
Benitoite 1·757 1·804
Corundum 1·761 1·770
Garnet (Almandine) 1·790
Zircon (a) 1·815
Garnet (Demantoid) 1·885
Sphene 1·901 1·985
Zircon (b) 1·927 1·980
Diamond 2·417