wherry: native element minerals 



451 



fNew; a combination of graphite with 



GRAPHITE GROUP. HEXAGONAL- -~ , , ,, . . 



< Dana s tellurium-arsenic group, ar- 



TRIGOXAL • J- + 



[ ranged in order of the periodic system. 



[ Name retained for the same reason as that 



Graphite (trigonal carbon)... C -j of diamond; "Cliftonite" is ameteoritic 



[ paramorph of graphite after diamond. 



Arsenic, trigonal As 



[ "Allemontite" (Dana No. 9). Classed as 

 a species by Dana, but there is no evi- 

 Antimonif erous . . . . As, Sb \ dence that it is anything but a variety 



of arsenic containing a variable amount 

 of isomorphous antimony. 



Antimony Sb 



Arseniferous Sb, As 



Bismuth Bi 



Tellurium, trigonal Te 



'Selentellurium" (Dana No. 6). Classed 

 as a species by Dana, but there is no 

 evidence that it is anything but a va- 

 riety of tellurium containing a variable 



Seleniferous Te, Se \ amount of isomorphous selenium. This 



selenium is present in a trigonal form, 

 which has not yet been discovered to 

 exist independently in nature, but has 

 been produced artificially. 



ORTHORHOMBIC-SULFUR GROUP. 



Sulfur, orthorhombic. 



elenif erous. 



S, Se 



Telluriferous S, Te 



MONOLCINIC-SULFUR GROUP. 



Sulfur, monoclinic S 



The "Sulphur group" of Dana. 



The spelling of this name with / instead 

 of ph is justified by history and usage 

 and has been adopted by the American 

 Chemical Society. 



Selensulphur" (Dana No. 4), "volcan- 

 ite." Classed as a species by Dana, 

 but there is no definite evidence that it 

 is anything but a variety of sulfur con- 

 taining a variable amount of isomor- 

 phous selenium; this selenium is pres- 

 ent in an orthorhombic form as yet un- 

 known independently. 



"Tellursulphur" 



J New; includes all non-metals and semi- 

 \ metals with monoclinic crystallization. 

 /3-sulfur," "7-sulfur." /3-sulfur is com- 

 mon around volcanoes, but is preserva- 

 ble only as a paramorph of orthorhom- 

 bic sulfur; 7-sulfur has been reported 

 "J to occur in nature by Vernadskii, Opuit 



