wherry: sulfide minerals 489 



sented by a comma, the element present in largest amount being 

 placed first; and in the case of complete isomorphous series and 

 double compounds the formulas are written separately, with a 

 period between, not implying any particular interpretation of 

 structure of the crystal, but so as to bring out to the best advan- 

 tage the numerical relationships between the constituents. 

 Variability in composition aside from typical isomorphism is 

 frankly admitted, and a dash placed between the numbers repre- 

 senting the limiting amounts of the variable elements. The 

 third column contains explanations of changes from current usage, 

 important synonyms, references for minerals omitted by Dana, 

 etc. 



SULFIDES, OXYSULFIDES, SELENIDES, TELLURIDES, AND CARBIDES OF 

 NON-METALS AND SEMI-METALS 



X: I DIVISION New; ratio X ranging from i + to 3. 



(New; placed by Dana after the "stibnite 

 group," but the formula-type is quite 

 different. 



f Synonyms: "gruenlingite," "joseite," (Dana 



Wehrlite Bii-2(Te,Se,S) \ No. 32), "oruetite," and "pilsenite;" com- 



[ position widely variable. 



NON-CRYSTALUZED GROUP New. 



(Hydrocarbons) H^C Chiefly cryptocrystalline. 



f Has been grouped with native elements, but 

 Quisqueite C2-3S { is apparently a compound; amorphous, 



[ colloidal. 



4:3 DIVISION New. 



DIMORPHITE GROUP. ORTHO- 

 RHOMBIC New. 



Has been confused with orpiment, but is 



Dimorphite AS4S3 1 evidently distinct. 



1:1 DIVISION New. 



MOISSANITE GROUP. TRIGONAL,- New. 

 HEMIMORPHIC 



fMeteoritic; the name "carborundum" has 

 priority, but was proposed for an artificial 

 product. 

 REALGAR GROUP. MONOCLINIC. 



Realgar AsS 



