MI. i MiuTKS, PHOSPHATES, ' 517 



B.B. Fuses ( -asil\ at L. 5, and yields a green flame (P|0|). In 



1\. !'. Mai-kens and becomes magnetic. "i 'it-Ids water in tin- C 

 tul)f. I )i>sol\vs in acid>. 



General description. Crystals are prismatic and flattened 



parallel to the orthopinacoid, which is often rounded and striated 

 lengthwise; also in interpenetrat ing >tellate groups, or radiated, 

 encrusted, friable, and earthy; at times replacing shells and roots 

 and fossil bones, and is then known as bone turquoise. 



Yivianite is a secondary mineral formed by the action of solu- 

 tions containing ferrous iron on apatite or other calcium phosphates 

 of organic origin. It occurs in the clays and gravel beds a.s blue 

 nodules at several localities in Monmouth County, New Jersey. 

 It is also associated with limonite, as at Stafford County, Virginia; 

 replacing roots in clay at Eddyville, Kentucky. Groups of large 

 crystals are obtained at Leadville, Colorado. 



ERYTHRITE 



Erythrite. Red Cobalt ; Cobalt bloom ; Hydrous arsenate of 

 cobalt, Co 3 (AO 4 ) 2 . 8 H 2 O ; CoO = 37.5, As 2 5 = 38.4, H 2 O = 

 '2 1 . 1 ; Monoclinic ; Type, Digonal Equatorial ; d : b : c = .7937 : 

 1 : .7356 ; p = 74 51' ; Common forms, a (100), b (010), m (110) ; 

 Cleavage, b perfect, a and w (101) distinct, very thin lamina flex- 

 ible and sectile; H. = 1.5-2.5; G. = 2.95; Color, crimson or shades 

 of retl and pink, sometimes grayish; Streak, pale; Luster, pearly 

 on cleavage faces ; Transparent to translucent. 



B.B. Fuses on coal to a dark globule and yields an arsenic 

 odor. In the closed tube darkens and yields water. With borax 

 yields a blue bead (Co). Dissolves in HC1 to a rose-colored solu- 

 tion. 



General description. Crystals prismatic, in stellate or radiated 

 aggregates; in drusy crusts or earthy. Associated with cobalt 

 MS an oxidation product. Beautiful radiated specimens are 

 obtained at Schneeberg in the Harz and at Freiberg in Saxony. 

 It is found as drusy crusts and as an earthy powder associated with 

 the cobalt ores of Cobalt, Ontario. 



Theeorrespondingnickel mineral, Annabergite, Ni 3 (AsO 4 ) 2 . 8H 2 O, 

 is apple green and is also found associated with the ores of cobalt 

 and nickel as an oxidation product. 



