776 



REPORT OF NATIONAL MUSEUM, 1897. 



THE /.KOLITKS. 



The zeolites — groups 50 to 01 — are silicates of aluminum with sodium 

 and calcium chietly, less ofteu strontium and barium. They are all 

 secondary minerals, all yield water upon ignition, and occur most com- 

 nvouly in cavities and seams of the more basic eruptive rocks. With 

 them are included three groups, G2 to 64, of minerals which, though 

 not true zeolites, are similar to them in general structure and occur- 

 rence. 



Group 50. 



MorcU'nite. 

 Ptilolite. 



Aiialcite. 



Eutliallite. 

 Eudnophite. 



Laumontite. 



Caporciauite. 

 Leonhardite. 



Gonuardite. 

 Lauljauito. 



Faujasite. 

 Erionite. 



Brewsterite. 

 Ileulandite, 

 Oryzite. 

 Epistilbite. 

 Stilbite. 



Phillipsite. 

 Haruiotome. 



Gmelinite. 



Lcvynitc. 



Chabazite. 



Phacolite. 



Acadialite. 



Haydeuite. 



H2CaAli(Si306)5.6H20. 



H.2(Ca,Nai,K2)(Si20f,)r,.6H,0. 



(iroup 51. 

 Na,Al,(Si0,)4.2H,0. 



Group 52. 

 CaAl,(SiO,)4.4H,0. 



Group 53. 



(Ca,Na2)2Ali(Si0:i)5.5iH.,0. 

 Ca.2A1.2(SiO;05.6H2O. 



Group 54. 



H..(Na.2,Ca)Al2(Si03)6.9H,20. 

 H.2Ca(Na2,K2)Al.(Si0;i)6.5H,0. 



Group 55. 



(Sr, Ba, Ca)3AlB( Si:,0«)6.9H,0. 

 Ca.,Al«(Si30s)6.16H.20. 



Ca3Al6(Si308)6.16H20. 

 Ca3Al,(Si,08)6.18H20. 



Group 56. 



Ca2(Na,K).2Al6(Si04).(Si308).14Ii,0. 

 Ba3Al6(Si04)3(Si30i,).14H20. 



Group 57. 

 Na3Al3(Si04)(Si308).2.9HnO. 



Ca3AlH(Si04):i(Si308)3.15H20. 



Ca:,Altt(Si04);,(Si308)3.18H20. 



Monoclinic. 

 Mouoclinic (?). 



Isometric. 



Monoclinic. 



Ortliorbombic (?). 

 Monoclinic. 



Isometric. 

 Orthorhombic (?). 



Monoclinic. 

 Mouoclinic. 



Monoclinic. 

 Monoclinic. 



Monoclinic. 

 Monoclinic. 



Hexagonal ; rbombo- 



bedial. 

 Hexagonal; rhombo- 



bedral. 

 Hexagonal ; rliombo- 



hedral. 



