A REVIEW OF THE AMORPHOUS MINERALS 539 



Gummite, alteration product of uraninite. 

 Glockerite, hydrous ferric sulfate. 

 Plumboniobite. 



Amorphous equivalent of thorite. 

 Amorphous equivalent of allanite. 

 Amorphous equivalent of gadolinite. 

 Amorphous equivalent of yttrotantalite. 

 Amorphous equivalent of homilite. 

 Amorphous equivalent of yttrocrasite. 

 Amorphous equivalent of pyrophyllite. 

 . Greenalite, hydrous ferrous silicate. 

 Yttrialite. 

 Neotocite. 

 Plombierite. 



Geolyte (Bodenzeolith), amorphous equivalent of zeolites. 

 Pochite. 



MINERALOIDS (HYDROCARBONS AND GLASSES) 



In addition to the foregoing definite amorphous minerals there 

 are several other classes of naturally occurring amorphous sub- 

 stances. I refer to the hydrocarbons and glasses. Shall they be 

 considered as minerals or not? The answer depends upon our 

 definition of the term mineral or mineral species. A mineral 

 (species) is usually defined as a naturally occurring homogeneous 

 substance of definite chemical composition. By common consent 

 the term is limited to the naturally occurring substances, although 

 the specific mineral name is often used for the corresponding arti- 

 ficial substance. No objection can be raised if the word synthetic 

 or artificial is prefixed to the mineral name. In view of the dis- 

 covery of solid solutions of a kind different from isomorphous mix- 

 tures in minerals, the definition given above must be modified 

 so as to read "of more or less definite chemical composition," as 

 suggested by Wherry. 1 



In the case of the hydrocarbons the principal objection against 

 considering them minerals is on account of their organic character. 

 While directly or indirectly the result of organic growth, they are 

 on a somewhat different footing from ordinary plant products. 

 They occur with other minerals in sedimentary rocks and are, in 



1 IMd., pp. 111-14. 



