Table 405 365 



index of refraction 



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 Dr. Edgar T. Wherry from a private compilation of Dr. Esper S. Larsen of the U. S. 

 Geological Survey. 



Mineral. 



Formula. 



Index of refraction. 



Ordinary 

 ray. 



Extraordinary 

 ray. 



(a) Uniaxial Positive Minerals. 



Ice 



Sellaite 



Chrysocolla . . . 



Laubanite 



Chabazite 



Douglasite .... 

 Hydronephelite 

 Apophyllite . . . 



Quartz 



Coquimbite . . . 



Brucite 



Alunite 



Penninite 



Cacoxenite. . . . 



Eudialite 



Dioptasite .... 



Phenacite 



Parisite 



\\ illemite 



\ esuvianite . . . 

 Xenotime .... 



Connellite 



Benitoite 



Ganomalite . . . 



Scheelite 



Zircon 



Powellite 



Calomel 



Cassiterite .... 



Zincite 



Phosgenite. . . . 

 Penficldite .... 



Iodyrite 



Tapiolite 



Wurtzite. ..... 



Derbylite 



Greenockite. . . 



Rutile. 



Moissanite .... 

 Cinnabarite . . . 



H 2 



MgF2 



CuO.SiO2.2H2O 



2CaO.Al2O3.5SiO2.6H2O 



(Ca, Na2)O.Ai203. 4 Si02.6H20 



2KCl.FeCl2.2H2O 



2Na2O.3AlaO3.6SiO2.7H2O 



K 2 O.SCa0.i6Si0 2 .i6H 2 



Si0 2 



Fe2O3.3SO3.9H2O 



MgO.H 2 



KiO.3Al2O3.4SO3.6H2O 



S(Mg, FelO.AbO3.3SiO2.4H2O 



2i-e20 3 .P20 5 .i2H20 



6Na 2 0.6(Ca, Fe)0.2o(Si, Zr)0 2 .NaCl 



CuO.SiO2.H2O 



2BeO.SK>2 



2CeOF.CaO.3CO2 



2ZnO.Si0 2 



2(Ca, Mn, Fe)0.(Al, Fe)(OH, F)0. 2 Si02 



Y;03.P 2 5 



2oCuO.S0 3 .2CuCl 2 .2oH 2 



BaO.Ti0 2 .3Si02 



6Pb0. 4 (Ca, Mn)0.6Si0 2 .H 2 



CaO.W0 3 



Zr0 2 .Si0 2 



CaO.MoOs 



HgCl 



Sn0 2 



ZnO 



PbO.PbCl2.COs 



Pb0. 2 PbCl 2 



Agl 



FeO.(Ta, Cb) 2 5 



ZnS 



6FeOSb203.5TiOs 



CdS 



Ti0 2 



CSi 



HgS 



(A) Uniaxial Negative Minerals. 



313 



39° 



S70 =*= 



486 



482 ± 



500 



502 



537 =*= 



553 



556 



580 



592 



579 



64S 



611 



707 



670 



757 



723 



718 ± 



816 



746 



804 



945 



934 



968 =fc 



978 



650 



°93 



029 



140 



210 



220 



420 (Li light) 



378 



510 (Li light) 



S29 



903 



697 



201 



Chiolite 



Hanksite . . . 



Thaumasite . 

 Hydro talcite 

 Cancrinite . . 

 Milarite 

 Kaliophilite . 



Mellite 



Marialite . . . 

 Nephelite. . . 



2 NaF.AlF 3 



11Na2O9SO3.2CO2.KCl 



3CaO.C02.Si0 2 .S03.i5H 2 



6MgO.Al 2 Oi.C0 2 .i5H 2 



4Na 2 0.Ca0.4Al2Oi.2C0 2 .9Si0 2 .3H 2 



K2O.4CaO.2Al2O3.24SiO2.H2O 



K 2 O.Al20 3 .2Si0 2 



A1jOj.Ci«09.i8HjO 



"Ma" = 3Na2O.3AhO3.18SiO2.2Nad 



Na20.Al 2 3 .2Si0 2 



• 342 

 .461 



.468 



• 498 

 .496 



• 529 



■533 

 •511 



• 537 

 .538 



Smithsonian Tables 



