134 



Classification of Natural Silicates. 



The Protopersilicates are grouped under the heads of Zeolitoid, 

 Spathoid, Adamantoid, Phylloid and Pinitoid ; while in a column 

 to the left are given the atomic ratios of fixed protoxyds and ses- 

 quioxyds, the silica being variable. The zeolitoids include, be- 

 sides the zeolites proper, forestite, prehnite, catapleiite, xanthor- 

 thite, etc. Under the spathoids of this class are placed petalite, 

 all feldspars and feldspathides, including sodalite, iolite and leu- 

 cite; the scapolites, including meionite ; barylite, milarite, gehle- 

 nite, sarcolite, melilite, wohlerite and eudialyte. The adamantoids 

 comprise pargasite, keilhauite, schorlomite, ilvaite, idocrase, gar- 

 net, allanite, beryl, euclase, ardennite, axinite, epidote, zoisite, 

 jadeite, spodumene, staurolite, sapphirine, and the various tour- 

 malines. In the phylloids are included the. micas proper, from 

 phlogopite and biotite, through seybertite and chloritoid, lepido- 

 lite, margarite and euphyllite to the muscovites and damourite. 

 "With the magnesian micas are placed, under the head of phyl- 

 loids, the whole family of chloritic species, while parallel with the 

 non-magnesian or muscovitic micas, are ranged the pinifcoids, 

 including besides pinite or gieseckite, jollyte, fahlunite, bravaisite, 

 cossaite and gunibellite. 



Order SILICATE. 



Sub-Order C— PERSILICATE. 



r :si. 



IvAOLINOID. 

 V = 6'8— 5*3 



Adamantoid. 



V = 5'3 — 4*4 



1 : H 

 1 : Vz 

 1 % % 

 1 : 1 

 1:1K 

 1:1X 

 1 : 2 

 1;2K 

 1 : 3 

 1 : 4 



Schrotterite. 



Collyrite. - 



Allophane. ----- 

 Pholerite. Samoite. - - 

 Kaolinite. Halloysite. 



Dumortierite. 



Topaz. Andalusite. Fibrolite. Cyanite. 



Bucholzite- Zircon. Malacone. 



Auerbachite. 

 Anthosiderite. 



$ Pyrophyllite. 



( Steargillite* Chloropal. 



Pyrophyllite. 



Cimolite- ----- 



Smectite. 



