120 NEW YORK STATE MUSEUM 



Olivenite Cu 2 (0H)As0 4 



Olivenite is a basic arsenate of copper. It occurs in small 

 orthorhonibic crystals of prismatic habit and often acicular; 

 also in velvety or drusy masses of fibrous crystals and in 

 globular forms. The luster is adamantine to vitreous and the 

 color olive-green of various shades passing to brown and some- 

 times almost black, more rarely yellow or grayish white. 



It is found in Cornwall, Devonshire, the Tyrol, the Ural 

 mountains, Chile and in the Tintic district of Utah. 



Libethenite Cu 2 (0H)P0 4 



Libethenite is a basic copper phosphate. It occurs in small 



orthorhonibic crystals closely resembling those of olivenite in 



form and luster; the color is in general somewhat darker than 



that of olivenite. T ,.^ 



Lazulite 



Lazulite is a basic phosphate of aluminium, iron and magnes- 

 ium. 



It occurs in monoclinic crystals of pyramidal habit and in 

 granular to compact masses. The luster is vitreous and the 

 color deep sky-blue. 



It occurs in veins in clay slate, quartzite, etc. and is found 

 in Salzberg, Styria, Sweden and in North Carolina and Georgia. 



Vivianite (blue iron earth) Fe 3 (P0 4 ) 2 +8H 2 



Vivianite is a hydrous phosphate of ferrous iron. 



It occurs in monoclinic prismatic crystals, often in stellate 

 groups; also as an earthy material replacing organic remains 

 as bones, shells, etc. The luster is vitreous to dull. The 

 unaltered material is colorless but gradually becomes blue or 

 bluish green on exposure to air. 



It occurs associated with pyrrhotite and pyrite in veins of 

 copper or tin, in beds of clay or associated with limonite; also 

 in cavities of fossils or buried bones. 



Vivianite occurs in the United States in New Jersey, Virginia 

 and Kentucky. 



Erythrite (cobalt-bloom) Co 3 (As0 4 ) 2 +8H 2 



Erythrite is a hydrous arsenate of cobalt. 

 It occurs in monoclinic prisms striated vertically and some- 

 times in stellate groups. Small globular and incrusting forms 



