620 MINERALOGY 



6. Gelatinizes in HC1 ; p. 674. 

 c. Insoluble in HC1 ; p. 675. 

 B. Fusibility above 5. 



1. Hardness below 5. 

 + . Yields water. 



a. Soluble in HC1 ; p. 677. 

 6. Gelatinizes in HC1 ; p. 678. 

 c. Insoluble in HC1 ; p. 678. 

 . Yields little or no water ; p. 679. 



2. Hardness above 5. 

 + . Yields water. 



a. Soluble in HC1 ; p. 679. 



b. Gelatinizes in HC1 ; p. 679. 



c. Insoluble in HC1 ; p. 680. 

 . Yields little or no water. 



a. Soluble in HC1 ; p. 680. 

 6. Gelatinizes in HC1 ; p. 680. 

 c. Insoluble in HC1; p. 681. 



PART I 



MINERALS WITH METALLIC OR SUB-METALLIC LL T STER 



I. The coat is white, and while being heated the assay yields an 

 arsenic odor. The presence of arsenic may be proven 

 by the tests on p. 585. 



A. When heated on coal, easily volatile without fusion. 



NATIVE ARSENIC, As; C. Tin-white; Str. Gray; Cl. 



Basal; H. 3.5; G. 5.7; III. 

 Fuses easily and volatilizes entirely. 

 Allemontite, As and Sb; C. Tin-white; Str. Gray; Cl. 



Basal; H. 3.5; G. 6.2; III. 



B. After heating on coal a non-volatile residue remains. 



1. Roasted and reduced with soda, yields silver ; p. 578. 



PEARCEITE, Ag 9 AsS 6 ; C. Black; Str. Black; H. 3; G. 

 6.15; F. 1; V. 



2. Roasted on coal, then moistened with HC1 and heated in 



the blue cone, yields an azure-blue flame (copper). 



