Reéxamination of American Minerals. 245 
sulphate appears to have formed. It is also found on fluor spar 
without associate. 
Some of the most beautiful specimens are where large crys- 
tals of anglesite are covered with crystals of carbonate of lead, 
these latter frequently penetrating the anglesite. 
49. Cerusite. 
The crystals of this mineral, though not as large as those of 
anglesite, are yet exceedingly beautiful, both in size as well as 
transparency ; the twin crystals are often two inches broad, trans- 
parent and presenting the appearance of the spread wing of a 
butterfly, some of the single crystals are an inch in length and 
half an inch thick. 
A transparent crystal weighing five grammes, gave a sp. grav. 
of 6-60 and on analysis furnished 
Carbonic acid, - - - - - 16°38 <) 22 5 
Oxyd of lead, RAIA asia at Ciel e es t = PbO 
100714 
of cerusite. It is found on galena without the association of any 
other mineral—on green and blue carbonate of copper—on pyro- 
Morphite which often covers the entire surface of the cerusite 
crystals, imparting to them an opaque yellowish green color—on 
of maganese in snow-white crystals, without any other as- 
sociate—on hematite in a similar manner; mamillary masses of 
the hematite sometimes pass through the crystals Some few spe- 
Cimens have been found consisting of crystals of galena, with a 
number of very fine hemitrope crystals of cerusite on the sur- 
face. The cerusite is occasionally covered with an exceedingly 
thin coat of oxyd of iron giving the crystals a dark red appear- 
ce, and some of them again with a very thin layer of pyro- 
_ Morphite, as delicate as if it had been put on with a brush. 
The cerusite is sometimes colored, black, Soil and yellow, in 
4 manner similar to that mentioned under ang’ 
50. Wulfenite. 
__ This mineral is found in small erystals of every shade of color 
from a light yellow to a bright red; it has been found in some 
