244 Reéxamination of American Minerals. 
48. Anglesite. 
This mineral is found abundantly and in beautiful crystals at 
this locality. The magnificence of many of the specimens ean 
only be realized by seeing those in Mr. Wheatley’s pode The 
crystals are remarkable for their size and transparency ;—in some 
instances, they weigh nearly half a pound being as trariep melee 
as rock crystal in nearly every part. Crystals with termina- 
tions at both ends have been-obtained five and a half inches 
in length by one and a half in js tapaane ; perfectly limped erys- 
tals an inch in length are quite commo 
The following are some of the Sveti: 
1.—0, @, 1-0. 
2.—0, 4-H, w-H,1, ¢,1-2,1-0, w-H. 
8.0, $B; $0, a; 1-9; 2:4 
4.—0, 4-0, w-®, 3-3, 1, w, 1-2, 2-4, 1-5. 
Sometimes the crystals of this mineral are full of cavities, £8 
of a milk-white color; but these do not differ in compositi 
from the colorless and transparent forms. It also occurs in circu- 
lar crystals. 
It is sometimes colored. There is a black variety produced by 
the more or less perfect admixture of the sulphurets of lead and 
copper (containing traces of silver) in the mass of the crystals, 
whose form is not altered. There are crystals of a delicate green 
color arising from carbonate of copper, and others of a yellow color 
oxyd of iron 
The transparent and colorless variety is remarkably pure. Its 
sp. grav. is 6°35. On analysis it afforded, 
Sulphuric acid, : . ; : aera O61 
Oxyd of sie, S - - : - 73°31 1322 
Silica, - - - - 20 
100-29 99°83 
oo very precisely with the formula Pb8. 
call attention to the method of analyzing this oe 
as jearibed 4 in another paper, for it was eo in the moist 
way by dissolving it first in citrate of amm ; 
The anglesite of this mine is found oui ieiike associated. It is 
common to find it in geodic cavities in galena, the cavities being 
lined with hematite varying in thickness from ,), to $ an ine neh 
or more, and often this hematite contains singloaits intimately - 
mixed in the mass. It may occur in crystals occupying a portion 
of the geode, or it may fill its entire capacity, assuming the form 
of the cavity. It is also found compacted in the galena without 
the appearance of any cavity or the presence of any other min- 
mi acicular crystals occur diffused through the galena. 
also on copper pyrites, with a thin layer of hematite inter- 
