Copper Minerals from Arizona. 23"J 



isb blue color, and containing cavities 3 to 4 cm. across, filled 

 with thin layers of chalcedony and druses of quartz, which 

 together form a compact coating over it. These cavities are 

 often 7.5 cm. across, and of remarkable beauty. The quartz 

 and chalcedony are thick enough to be susceptible of a polish, 

 or the £an£ue can be cut with it, and thus a curious and attract- 

 ive gem-stone can be made. The handsomest mineral of this 

 description comes from the Old Globe mine in Gila County. 



Chrysocolla, in beautiful blue patches 1 to 2 cm. across, occurs 

 in an impure black oxide of copper, making an exceptionally rich 

 combination. The handsomest form, however, (and perhaps no 

 finer was ever found,) is the glassy-green chrysocolla from the 

 Clifton district. It is filled with transparent green flakes 25 

 mm. long, 6 mm. wide, and 3 mm. thick, and penetrated by 

 tubular hollows like the centres of stalactites. Another form 

 consists of dark blue or bluish-green surfaces, from 7.5 cm. to 

 25 cm. across, only as a thin coating. This is equal in beauty 

 to that from any other known locality. 



Cuprite. 



This species occurs in brilliant red crystals of cubic form, 

 measuring from 1 to 5 mm., in groups of several dozen crystals 

 embedded in massive cuprite and associated with native copper, 

 from the Clifton group of mines, Graham Co., Arizona. It is 

 also found in very dark cochineal-red crystals, almost black in 

 fact, associated with malachite and calcite. One fine cube, 

 coated with acicular crystals of calcite, measures 8 mm., and one 

 fractured crystal 10 mm. One group, 3.5 cm. by 6 cm., con- 

 sisting of several hundred cr} 7 stals, principally elongated cubes 

 from 1 to 3 mm. wide, has, in addition to the elongated form, 

 crystals of the simple octahedron, the cube, and dodecahedron, 

 and the cubo-octahedron and dodecahedron combined. The 

 crystals from the Copper Queen Mine are from .5 to 1 mm. in 

 size, and are simple octahedrons sharply defined, of a deep red 

 color, implanted on malachite coated with limonite. 



These crystals are usually white, but the color is due to a film 

 which can be easily removed bytwashing. 



Dioptase is obtained in beautiful bluish-green crystals 5 mm. 

 in diameter, from the Clifton District ; also native copper of a 



