Van Rom— Silver, Copper, and Cobalt Minerals. 29 



Cuprite. — This is found mostly massive granular, associated 

 with malachite, azurite, and gypsum. It is also present in 

 brilliant ruby red crystals on the copper cubes shown in fig. 1. 

 These crystals are very small and could be recognized only as 

 cubes modified by at least two other forms. 



Hematite. — It occurs chiefly as earthy masses in the lime- 

 stone. It is found in botryoidal and stalactitic forms at the 

 Esmeralda mine in the same district. 



Limonite. — This mineral has the same occurrence as hema- 

 tite, both in the Veta Rica and Esmeralda mines. 



Caleite. — As has been stated previously, calcite does not 

 seem to be common as a gangue mineral in this locality. It 

 was found in one place as small doubly terminated scaleno- 

 hedral crystals in drusy cavities with argentite and silver. On 

 another specimen, it was seen in granular masses with proustite 

 in seams in limestone. 



Cerussite. — Cerussite occurs in granular, almost friable, 

 masses, in large quantities in the upper levels, where it is 

 associated with gypsum and sulphur. It was the original ore 

 of the camp, and is still important. It always contains silver 

 values in paying quantity. Cerussite was also seen as a coating 

 on galena. 



Malachite. — This mineral is found in small acicular crystal 

 aggregates and coatings with azurite, cuprite, and gypsum. 



Azurite. — Azurite is present in tabular crystal aggregates, 

 and has the same association as malachite. 



Erythrite. — This mineral is found rarely in single crystals, 

 but generally occurs in stellate and rosette-like crystal aggre- 

 gates which have a beactiful peach pink to nearly crimson color. 

 The earthy varieties so common at Cobalt, Ontario, and elsewhere 

 were not observed. The crystals are all distinctly tabular after 

 the large clinopinacoid (010), which habit has not been previ- 

 ously observed. Other forms noticed were a prism, a positive 

 pyramid, a negative orthodome, and probably also the ortho- 

 pinacoid (100), all of which were small. The two terminal 

 forms are somewhat rough, and the dome face is always larger 

 than the pyramid. With the exception of the pronounced 

 tabular habit, the crystals resemble the drawing made by 

 Green. * The crystals were striated vertically, aud the cleavage 

 after the clinopinacoid was perfect. The luster on the cleavage 

 face was pearly, and elsewhere was vitreous. The mineral 

 occurs in little veins and cavities in barite, and is also associated 

 with silver. In all places, however, the silver rested upon the 

 erythrite, and, therefore, was deposited later. No cobalt arsen- 

 ides or other cobalt minerals have ever been observed from 



* Crystallization of Erythrite from Cobalt, by W. F. Green, Trans, of the 

 Canadian Institute, viii, 443, 1908-9. 



