DESCRIPTION OF PHOSPHATED COPPER. 359 



Phosphated copper may be distinguished Distinguishing 



1, from green carbonate of copper, by dissolving Jn '^^^'■^'^^'■''^• 

 nitric acid without effervescence, and giving a blue colour: 



2, from muriate of copper, by not giving a blue and 

 green colour to flame, on which it is thrown, as the mu- 

 riate does : 



3, from arseniated copper, by not emitting an arsenical 

 smell when acted on by fire, and giving a blue colour, 

 instead of a green, to nitric acid. 



The crystals of phosphated copper are commonly grouped Varieties of 

 so as to exhibit but one face, or one solid angle. The ™* 

 faces are seldom plane and smooth, being almost always 

 curved, and subdivided into a great number of small facets 

 with different inclinations. When the faces are smooth 

 and plane, they appear as if striated parallel to one of the 

 edges : and in these crystals we perceive two opposite faces, 

 which are neither plane nor smooth, but rough and full of 

 little points. The form of these crystals appears to be a 

 rhomboid, approaching to a cube. 



Single or detached crystals are occasionally found. 

 These exhibit a rhomboid apparently more acute than the 

 preceding ; but neither their faces nor edges are sharp and 

 well defined. 



Sometimes it occurs in small scales, lying on each other, 

 and inclined in different directions. 



The fibrous phosphate of copper is found either in 

 masses externally drusy; or lining cavities. This variety 

 exhibits internally fine and close striae, arranged in bundles 

 of divergent radii, issuing from one or more centres. This 

 variety has sometimes a silky or satiny lustre within. 



The phosphated copper just described is found in the Where found. 

 bed or vein called Venusberg, or Josephberg, not above 

 half an hour's journey from the town of Rheinbreitbach. 

 I have said bed or vein, because, if examined in different 

 places, it appears sometimes one, sometimes the other; and 

 hence mineralogists are not decided which to call it. I am 

 inclined however, to consider it as a vein, from the resem- 

 blance between this mountain and that of Mariaberg, 

 which contains unquestionable veins of pyritous copper, 

 and is not above 20 or 25 minutes distant from that in 

 which the phosphated copper is found. 



The 



