Table 343 {continued), 



INDEX OF REFRACTION. 



Selected Biaxial Minerals. 



287 



Mineral. 



Formula. 



Index of refraction. 



(a) Biaxial Positive Minerals (continued). 



Zoisite 



Strengite 



Diasporite .... 



Staurolite 



Chrysoberyl. . . 



Azurite 



Scorodite 



Olivenite 



Anglesite 



Titanite 



Claudetite .... 



Sulfur 



Cotunnite 



Huebnerite. . . . 

 Manganite. . . . 



Raspite 



Mendipite 



Tantalite 



Wolframite . . . 



Crocoite 



Pseudobrookite 

 Stibiotantalite. 

 Montroydite . . 



Brookite 



Lithargite 



(b) Biaxial Negative Minerals. 



Mirabilite 



Thomsenolite. . 



Natron 



Kalinite 



Epsomite 



Sassolite 



Borax 



Goslarite 



Pickeringite. . . 



Bloedite 



Trona 



Thermona trite 



Stilbite 



Niter 



Kainite 



Gaylussite . . . . 



Scolecite 



Laumontite . . . 

 Orthoclase . . . , 

 Microcline . . . . 

 Anorthoclase . . 

 Glauberite . . . . 



Cordierite 



Chalcanthite . . 

 Oligoclase 



Na20.SOs,ioH20 



NaF.CaF2.AlF3.H2O 



Na20.C02.ioH20 



K2O.AI2O3.4SO3.24H2O 



MgO.SO3.7H2O 



B203.H20 



Na20.2B203.ioH20 

 ZnO.SO3.7H2O 



MgO.Al203.4S03.22H20 



Na2O.MgO.2SO3.4H2O 



3Na2O.4CO2.5H2O 



Na2O.CO2.H2O 



(Ca, Na2)O.Al203.6SiOj.5H20 



K2O.N2O5 



MgO.SO3.KCl.3H2O 



Na2O.CaO.2CO2.5H2O 



CaO.Al2O3.3SiO2.3H2O 



CaO.Al2O3.4SiO2.4H2O 



K20.Al203.6Si02 



Same as preceding 



(Na, K)20.Al203.6Si02 



Na2O.CaO.2SO3 



4(Mg, Fe)0.4Al203.ioSi02.H20 



CuO.SO3.5H2O 



Ab4An 



1.594 

 1.407 

 1-405 

 1-430 

 1-433 

 1.340 

 1-447 

 1-457 

 1-476 

 1.486 

 1. 410 

 1.420 

 1-494 

 1-334 

 1-494 

 1-444 

 I. 512 

 I-S13 

 1-518 

 1-522 

 1-523 

 1-515 

 1-534 

 1-516 

 1-539 



398 

 415 

 440 

 458 



461 



459 

 472 

 484 

 483 

 489 

 542 

 518 

 500 

 506 

 516 

 523 

 S19 

 52s 

 526 

 530 

 531 

 536 

 S40 

 546 

 547 



Sm'thsonian Tables. 



