OBSERVATIONS. 29 
fubftances) produces fometimes alfo the 
two following cryftallizations, the nature 
of which was till now unknown. 
\ '• ' • ■ , ' 
The firft of thefe (which lines the 
cavities of a cryftallized crumbled quartz, 
partly uncovered, and partly coated with 
indurated green copper, and alfo with dark 
brown velvet-like iron ochre) confifts of 
tender, olive-green coloured fpiculae j thefe 
are about two or three lines long, and ftand 
ftraight up either Angle or fafciculated and 
radiated. They con fid: of copper mine¬ 
ralized by the acid of arfenic. When I 
tried them with the blowpipe, they de¬ 
flagrated with arfenical fmoke, and then 
fufed, forming a button of a grey colour, 
which when melted again with borax, 
gave inftantly a button of very pure 
coppei*. 
The other cry dais in my fpecimen, 
are very fmall, aggregated dark green 
cubes with fmooth and (hining furfaces 
upon grey copper ore in a mafs of cryf¬ 
tallized compact quartz with cavities in 
it. 
