288 



Table 843 {cotUiimed). 

 INDEX OF REFRACTION. 

 . Selected Biaxial Minerals. 



Mineral. 



Formula. 



Index of refraction. 



(6) Biaxial Negative Ckvstals {continued). 



Beryllonite. . . . 

 Kaolinite .... 



Biotite 



Autunite , 



Anorthite 



Lanthanite.., . 

 Pyrophyllite . . 



Talc 



Hopeite 



Muscovite . . . . 

 Amblyeonite . . 



Lepidolite 



Phlogopite. . . . 



Tremolite 



Actinolite 



Wollastonite . . 



Lazulite 



Danburite . . . . 

 Glaucophanite 

 Andalusite. . . . 

 Hornblende . . . 



Datolite 



Erythrite 



Monticellite.. . 

 Strontianite. , . 



Witherite 



Aragonite 



Axinite 



Dumortierite. . 



Cyanite 



Epidote 



Atacamite . . . . 



Fayalite 



Caledonite. . . . 



Malachite 



Lanarkite 



Leadhillite 



Cerussite 



Laurionite . . . . 



Matlockite 



Baddeleyite. . . 

 Lepidocrocite. , 



Limonite 



Goethite 



Valentinite 



Turgite 



Realgar 



Terlinguaite. . . 

 Hutchinsonite. 

 Stibnite 



Na2O.2BeO.P2O5 



Al2O3.2SiO2.2H2O 



K20.4(Mg, Fe)0. 2.'y20j.6SiOfcHsO 



CaO.2UO3.P2O6.8H2O 



"An" = CaO.Al203.2SiO» 



La2O3.3CO2.9H2O 



Al2O3.4SiO2.H2O 



3MgO.4SiO2.H2O 



3ZnO.P2O6.4H2O 



K20.3.Al203.6Si02.2HjO 



Al2a.P2O5.2LiF 



Al203.3Si02.2(K,Li)F 



K2O.6MgO.Al2O3.6SiO2.2H2O 



Ca0.3MgO.4Si02 



Ca0.3(Mg, Fe)0.4Si02 



Ca0.Si02 



(Fe, Mg)O.Al2a.P206.H20 



CaO.Bz03.2Si02 



Na20. 2FeO. Al2O3.6Si02 



AhOj.SiOz 



Contains Na20, MgO, FeO, SiO:, etc. 



2CaO.2SiO2.B2O3.HjO 



3CoO.As2O5.SHjO 



CaO.MgO.SiOj 



SrO.COj 



BaO.C02 



CaO.C02 



6(Ca, Mn)0.2Al203.B203.8Si02.H20 



8 AI2O3. B2O3.6SiO2.HjO 



AWs.SiOj 



4Ca0.3(Al, Fe)203.6SiOs.HjO 



3CuO.CuCl2.3H2O 



2FeO.Si02 



2(Pb, Cu)O.S03.H20 



2CuO.CO2.H2O 



2PbO.S03 



4PbO.SO3.2CO2.H2O 



PbO.C02 



PbCl2.PbO.H2O 



PbO.PbCh 



Zr02 



Fe203.H20 



2Fe203.3H20 in part 



FeiOs.HiO 



SbjOs 



2Fe203.H20 in part 



AsS 



Hg20Cl 



(Tl, Ag)2S.PbS.2As2S3 



Sb2S3 



Smithsonian Tables. 



