524 



TABLE 546.— INDEX OF REFRACTION OF SELECTED UNIAXIAL MINERALS 



The values are arranged in the order of increasing indices for the ordinary ray and are for the 

 sodium D line unless otherwise indicated. Selected by Edgar T. Wherry from a private com- 

 pilation of Esper S. Larsen, of the U. S. Geological Survey. 



Uniaxial positive minerals 



Mineral Formula 



Ice H 2 



Sellaite MgF 2 



Chrysocolla CuO-SiGv2H 2 



Laubanite 2CaO-Al 2 Gv5SiGv6H 2 



Chabazite (Ca, Na 2 )0-Al 2 Gv4Si0 2 -6H 2 



Douglasite 2KCl-FeCV2H,0 



Hydronephelite ... 2Na 2 O3Al 2 3 -6SiGv7H 2 



Apophyllite K 2 0-8CaO- 16SiGV 16H 2 



Quartz Si0 2 



Coquimbite Fe 2 Gv3SGv9H 2 



Brucite MgOH 2 



Alunite K 2 0-3Al 2 Gv4SGY6H 2 



Penninite 5(Mg, Fe)0- Al 2 Gv3SiGv4H 2 



Cacoxenite 2Fe 2 3 ■ P 2 5 ■ 12H 2 



Eudialite 6Na 2 0-6(Ca, Fe)O-20(Si, Zr)0 2 -NaCl 



Dioptase CuO-Si0 2 -H 2 



Phenacite 2BeO-Si0 2 



Parisite 2CeOF • CaO ■ 3C0 2 



Willemite 2ZnO-Si0 2 



Vesuvianite 2(Ca, Mn, Fe)0- (Al, Fe) (OH, F)0-2Si0 2 



Xenotime Y 2 3 - P 2 5 



Connellite 20CuO-SO 3 -2CuCl 2 -20H 2 O 



Benitoite BaO-Ti0 2 -3Si0 2 



Ganomalite 6PbO-4(Ca, Mn)0-6Si0 2 -H 2 



Scheelite CaO-W0 3 



Zircon ZrGV Si0 2 



Powellite CaO-Mo0 3 



Calomel HgCl 



Cassiterite Sn0 2 



Zincite ZnO 



Phosgenite PbO-PbCl 2 -C0 2 



Penfieldite PbO-PbCl 2 



Iodyrite Agl 



Tapiolite FeO • (Ta, Nb) 2 5 



Wurtzite ZnS 



Derbylite 6FeO-Sb 2 3 -5Ti0 2 



Greenockite CdS 



Rutile Ti0 2 



Moissanite CSi 



Cinnabar HgS 



Uniaxial negative minerals 



Chiolite 2NaF-AlF 3 



Hanksite llNa 2 0-9SGv2CGvKCl 



Thaumasite 3CaO-CGvSiGvSGvl5H 2 



Hydrotalcite 6MgO- A1 2 3 -C0 2 -15H 2 



Cancrinite 4Na 2 0-CaO-4Al 2 3 -2C0 2 -9Si0 2 -3H 2 



Milarite K 2 0-4CaO-2Al 2 3 -24Si0 2 -H 2 



Kaliophilite K 2 0- Al 2 Gv2Si0 2 



Mellite A1 2 3 -C, 2 0,- 18H 2 



Marialite "Ma" — 3Na 2 0-3Al 2 Gvl8Si0 2 -2NaCl 



Nephelite Na 2 0- Al 2 Gv2Si0 2 



Wernerite Me,Ma, ± 



Beryl 3BeO Al 2 3 -6Si0 2 



Torbernite CuO-2UGvP 2 Gv8H 2 



Meionite "Me" = 4CaO-3Al 2 3 -6Si0 2 



Melilite Contains Na 2 0, CaO, A1 2 3 , Si0 2 , etc. 



{continued) 



SMITHSONIAN PHYSICAL TABLES 



