4 5 
_ Sulphate of lead, called native lead-vitriol by 
Werner, crystallized and massive.— Lead earth , 
indurated and friable, of various colours ; its dif¬ 
ferent varieties appear to be related to carbo¬ 
nates, phosphates, and sulphates of lead: to which 
latter also the reniform lead ore (blei-niere of 
Werner) from Siberia appears to belong : some 
varieties of lead earth are oxides. Near to these 
is also placed the native minium , from Hessia, 
first described by Mr. Smithson, and varieties of 
the same from Siberia ; all of them probably 
produced by the decay of galena. 
(Case 44.) Ores of zinc. Among the many va¬ 
rieties of sulphuret of zinc , or blende, may be par¬ 
ticularized those relative to colour, viz. the yel¬ 
low, the brown, and the black blende of Werner; 
the first of which is generally most pure, while 
the two others contain a portion of iron; the 
fibrous blende of Przbram in Bohemia, in which 
the cadmium was discovered by Stromeyer ; the 
variety called testaceous blende (schaalen-blen- 
de), the most characteristic specimens of which 
are from Geroldseck in the Brisgau, contains, 
besides iron, a portion of lead.—The other ores 
of zinc in this case are those of a sparry appear¬ 
ance, commonly called calamine, which constitute 
three different species, viz. the electric or siliceous 
calamine, in a variety of which the presence of 
cadmium has been announced by the late Dr. 
Clarke *, the common calamine, or native carbo¬ 
nate of zinc 5 and the red oxide of zinc : the speci- 
S A LOON. 
Nat. Hist. 
mens 
