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%% M INERALO. GICAL 
vered this unknown ore to be Sulphurated . 
tin. 
The firft, and, until now, the only in- 
ilance of a native fulphurated tin, is men¬ 
tioned by Mr. Bergmann. He received it 
under the name of antimony from Siberia, 
and the fpecimen was only of the fize 
of a hazle-nut, As fulphurated tin-ores 
then are fo very fcarce, an account of the 
exigence of a large vein in Cornwall can¬ 
not fail to be agreeable to mineralogifts. 
My fpecimens confift of the compadt 
ore, only here and there are marks of 
growan, which is the matrix of it. 
The colour of this ore is, in general, a 
blueifh white, approaching a heel-grey, 
and comes near the colour of grey cop¬ 
per ore. Its cohefion is in feverai places 
interrupted by cracks, often fcarcely per¬ 
ceptible, filled with a very thin layer of 
yellowifh and greenith clayey earth : from 
this caufe the external texture feems 
lamellar, but the frefh fradture is gene¬ 
rally irregularly angular. The metallic 
