HIIXEBRAND.1 
NOTES ON PROSOPITE. 
G7 
variscite called by him utablite in Mineral Resources of the United 
States, 1894, page 002. Under a recent date Mr. Kunz writes that Mr. 
T. H. Beck, of Provo, Utah, found the mineral u in 1895, in the Dugway 
mining district, Tooele County. It was found in a low range of hills 
about 5 miles long, surrounded by a desert on an arid region occurring 
as flat rock, associated with fluorite, native silver, slate, and trachytic 
rock ( !), containing decomposed pyrite in which there was present a 
little free gold." 
Unexpectedly this was found to be the hydrous aluminum-calcium 
fluoride prosopite, mixed with some quartz and probably fluorite, and 
colored by a small amount of some copper salt. A new and interesting 
occurrence for this very rare mineral is thus afforded. 
The material as prepared for analysis after separation by a heavy 
solution proved to be still far from pure; quartz grains in amount from 
1 to 2 per cent were left undissolved after complete conversion of the 
fluorides into sulphates, and presumably considerably more had been 
removed by the escaping fluorine. The total amount of quartz was 
not determined, and the material at hand did not suffice for attempts at 
more complete purification, so that the conclusions drawn from the 
analysis, while extremely probable, are not to be taken as altogether 
proven. 
The specific gravity of the mineral as analyzed was 2.87 at 21° C. 
and the hardness about 4.5, both agreeing with the constants for proso- 
pite. Furthermore, but little of the water (1.25 per cent) was expelled 
by several hours heating at 280° 0. Analysis gave: 
Al 
Ca 
Mg 
K 
Na 
Cu 
F 
H 2 
Quartz and oxygen 
20.08 
17. 55 
trace 
.12 
.32 
.17 
28.00 
14.24 
19.52 
100.00 
Neglecting copper, alkalies, and the oxygen calculated for their 
oxides, and assuming the water to exist entirely as hydroxyl, the fol- 
lowing not very satisfactory atomic ratios result : 
Al 7407 2 
Ca 4380 1.18 
F 1.4690] 8 23 
Hydroxyl 1.58081" 
