GENERAL MINERALOGY OF THE DISTRICT. 
125 
the Josie S. shaft near the Humboldt prospect, at the head of Squaw Gulch. Later 
the mineral was also identified from the Wild Horse lode. Doctor Hillebrand states 
that it does not seem to be wholly anhydrous. At both places the mineral occurs 
in the oxidized zone and forms small white, bluish, or yellowish prisms and groups 
of crystals. It is directly associated with limonite and kaolin and evidently 
deposited during the process of oxidation. There is, however, a second mode of 
occurrence of celestite in Cripple Creek. In slender needles it coats the open vugs 
in the vein fissures far below the line of oxidation, and here it certainly seems to 
be one of the primary vein minerals. 
The needles are combinations of the dome (Oil) and the pyramid (144), the 
curved sides of the prisms being due to the oscillatory growth of these two crystal 
forms. The crystals resemble in habit the pseudomorphs of calcite after celestite 
found at Obersdorf, near Sangerhausen, Thuringia, and the celestite crystals of 
Mineral County, W. Va. It was identified from the C. K. & N. mine. In most 
cases these delicate needles and prisms have been transformed into acicular pseud¬ 
omorphs of fine-grained quartz, or are coated by quartz crystals, while the original 
substance has been dissolved. These are found more or less abundantly in the 
majority of veins in the district, but are especially plentiful in the Howard flat 
vein in the Ophelia tunnel, where they line a large cavity 2 or 3 feet in width. The 
pseudomorphs are found in some collections labeled cpiartz after stibnite, which 
of course is erroneous. 
A third mode of occurrence is as principal gangue in a vein on the 660-foot 
level of the Ironclad mine. The mineral is granular and partly crystallized, white 
or yellowish, and is associated with some oxidized lead ore. Here, too, celestite 
is doubtless a primary gangue mineral. 
Alunite .—This mineral was identified from level 5 of the Last Dollar mine; 
it follows the vein fissure as a rather hard and compact, fine-grained, white sub¬ 
stance, looking very much like kaolin. It was also noted from the adjoining 
Modoc mine and probably occurs at many other places. It seems to be confined 
to the oxidized zone. 
Gypsum .—Occurs in large masses in the Deerhorn shaft, associated with 
flourite and pyrite, and seems also to be fairly common in decomposed vein matter. 
Glockerite (2Fe 2 0 3 S0 3 + 6H 2 0).—This mineral was identified with considerable 
certainty by R. Pearce® in an oxidized ore from the Modoc mine. The same or 
similar ferric sulphates are probably of common occurrence in the upper levels of 
the mines. 
In the Ophelia tunnel a brown, sticky substance drips from the back and forms 
rosinlike crusts on the floor. It accumulates only during the winter. According to 
Hillebrand, it consists of a mixture of hydrous sulphates of ferric iron, alumina, zinc, 
and perhaps a little of the alkali me als. It also contains some phosphates, but no 
lime or magnesia. While essentially a mixture, it probably contains glockerite. 
Basic hydrous strontium sulphate .—This new mineral occurs as an impalpable 
white powder covering granular celestite in a vein on level 7 of the Ironclad mine, 
described on page 286. Under the microscope it proves to consist of short and 
a Further notes on Cripple Creek ores: Proc. Colorado Sci. Soc., vol. 5, 1894-1896, p. 13. 
13001—No. 54—06-10 
