30 Foreign Notices in Mineralogy, ec. 
I conceive its primary form to be a right prism, whose base 
is an oblique-angled parallelogram of 59° an 
But the crystals i have, are too imperfect to determine this 
point ibs precision, or to give the height of the prism. 
The sulphato-tri-carbonate consists of 
1 atom sulphate, Fiona. 
“* carbonate, jaf le of 
aoa gravity, 6.3 to 
ardness between arte of lead and cupreous sul- 
phate-carbonate. 
Colour of the rhomboidal erystals: pale greenish, or yel- 
lowish, or brownish, or colourless and transparent, when 
very minute. 
The prismatic varieties are colourless, or of various 
aes of pale yellow. The rhomboids are acute, meas- 
ring 72° 30” and 107° 30”; and from not having found 
anj-cietalieti e than one perpendicular to the axis of 
the crystal, I am Ee odacdd to adopt this as the primary f orm. 
_ The principal modifications I have observed, are 
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 whieh there are three or four? 
The natural planes of all except the most minute crystals 
are more or less rounded, and consequently waren imper- 
fect reacting, 
The cio Aire aloe iteoms appears, from the sep- 
arate analysis o 
3.59 grs. > 
girs.) to eer ee Cif the carb. of cop- 
&. = ts atoms se Maco of lead, ) per be chemically 
| eee : _ carbonate, ) _ ) combined, “oe not 
We Bed ane a of copper, accidental. 
ie grav is about 6 
_ Flaine ss between pre of lead and sulphatorti- 
ae blue to dark seeanigh- bits 
The primary form is a right. prism, with ends! a recta: 
gular or rhombic base. From the indication. of jo o 
allel to all the planes of the latter; and pair i 
