119 
found at Lead! nils. 
Specific gravity, 6.3 to 6.d* 
Hardness between sulphate of lead and cupreous sulphato- 
carbonate. 
Colour of the rhomboidal crystals pale greenish, or 3 /ellowish, 
or brownish, or colourless and transparent, when very minute. 
The prismatic varieties are colourless, or of various shades of 
pale yellow. The rhomboids are acute, measuring 72° 30' and 
107 ° 30'; and from not having found any other cleavage than 
one perpendicular to the axis of the crystal, I am induced to 
adopt this as the primary form. 
The principal modifications I have observed, are those which 
pass into the six-sided prism by the truncation of all the solid 
angles of the rhomboid, and those which produce more obtuse 
rhomboids, of which there are three or four. The natural 
planes of all except the most minute crystals are more or less 
rounded, and consequently afford imperfect reflections. 
The Cupreous sulpliato-Carbonate appears, from the separate 
analysis of* 
3.59 grams, a consist of 6 atoms sulpfhate \ 1 if the carb. of copper be 
... f ^ carbonate j ’ > chemically combined, 
141 ** I ^ carbonate of copper, j and not accidental. 
Specific gravity about 6.4. 
Hardness between carbonate of lead and sulphato-tri-carbo- 
nate. 
Colour blue to dark greenish-blue. 
The primary form is a right prism, with either a rectangular 
or rhombic base. From the indication of joints parallel to all 
the planes of the latter, and from not having observed any joints 
parallel to more than four of the planes of the rectangular prism, 
I consider the right rhombic prism as the primary form. The 
angles of this prism are 95° and 85° ; the planes which give the 
angle of 95° appear on many of the crystals as a dihedral ter- 
mination to secondary forms, analogous to some prismatic varie- 
ties of sulphate of barytes. The crystals are generally very mi- 
nute, and appear sometimes in small bunches, radiating from 
their common point of attachment to the matrix. 
Besides the cleavages parallel to its planes, the rhombic prism 
divides also in the direction of its shortest diagonal, and its height 
is to the edge of the base as 2 to 1 , 
