10 University of California Publications in Geology. [Vol. 7 



Some coatings incline toward a green color and seem to grade 

 into embolite. The crystals are very minute in size and form 

 perfect cubes with generally the octahedron. Some are distorted 

 into prismatic shapes and others are twisted and curved and 

 show evidences of having been formed from dripping solutions. 



Spurr 3 cites the occurrence of cerargerite as an inclusion in 

 primary argentite and advances the possibility of the formation 

 of the hornsilver by the solvent action of the same solutions which 

 deposited the original sulphides. It is possible and even probable 

 that some chlorine was present in the original ascending solutions 

 and that some cerargerite may have been formed, but it appears 

 undoubted that surface waters brought in the bulk of the chloride 

 and accomplished the main oxidation of the deposit. 



Embolite. — The chloro-bromide is not so abundant as the 

 simple chloride or iodide, and it is chiefly found intermediate 

 between the two. It occurs in bunches and groups of green, 

 imperfectly formed crystals, often implanted on psilomelane. 

 The crystals are highly deformed cubes and octahedrons, with 

 sometimes the rhombic dodecahedron. 



In the crystallization of the cerargerite considerable bromine 

 was taken up, so the amount of embolite present in the mines does 

 not represent the original quantity of bromine carried in the 

 solutions. 



Iodyrite. — Bromine so generally accompanies chlorine that 

 embolite is a characteristic associate of cerargerite in deposits 

 containing important amounts of the latter. Iodine on the other 

 hand is very rare, and the Tonopah deposit is quite exceptional 

 in having iodyrite in a comparatively large quantity. The iodide 

 is mostly confined to the lower depths of the oxidized zone. It is 

 present as small loose crystals in the cavities and fissures of the 

 veins, and as brilliant crystalline crusts and coatings on the walls 

 of fissures. One of the largest pockets of loose crystals was 

 found in the Valley View vein, a few feet above the 500-foot 

 level. It contained a host of deep yellow crystals mixed with 

 small fragments of stalactitic and conchoidal psilomelane. The 

 crystals also occur characteristically with flaky brown and yellow 



s Loc. ext. 



