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MINER ALOGICAL 
Native copper, of a tender and mofs- 
like form, united to ruby vitreous copper" 
ore, cryftallized in rhombs, is found in 
the clefts of mountains, compofed of 
Killas, at Poldory. Very fmall particles 
of native copper are interfperfed through 
Goflan at Kaftle Adit. 
On fome parts of the native copper- 
ores from Poldory and Huel Virgin, is 
found calciform - copper - ore, fometimes 
only in a loofe form, and covering them 
like fand, fometimes of a compact ftruc- 
ture, and adhering ftrongly to them. 
The former kind is generally black, the 
latter of a brownifh red, often approach¬ 
ing to the metallic Iplendor of copper. 
One may generally obferve in thefe ores 
from Cornwall various gradations, calci¬ 
form copper-ores, vitreous copper-ores 
and native copper: but I do not pretend 
to aflert whether the metal is reducing or 
calcining. 
Of fulphurated copper ores, Cornwall 
has an abundance of various kinds. 
Whitifh 
