CHEMICAL STUDY OF DOLOMITES 
39 
2. Hell Fire Rock, Wahsatch Mountains, Utah . — The analysis 
revealed that it is quite a pure sandstone, and can not be classed 
with the dolomites. The rock is white, crumbly, and fine granu- 
lar in appearance. The specific gravity is 2.2. 
PER CENT 
SiOg 95.29 
Fe^Og '.. 2.88 
Alfi^ 1.68 
CaCOg 0.16 
MgCOg 0.00 
100.01 
J. Specimen from Hurley, Wisconsin . — The sample contained 
a number of quartz crystals, also iron pyrite and siderite. The 
exterior bore a number of dolomite crystals of a pinkish hue, and 
only the dolomite crystals were taken for the analysis. The speci- 
men proved a fairly typical dolomite. We did not determine the 
specific gravity. 
PER CENT 
SiO^ 2.56 
Fe^03 0.27 
ALO3 0.00 
CaCOg 48.52 
MgCOg 40.02 
100.37 
4. Specimen from Brosso, Piedmont, Italy . — This sample has 
a peculiar appearance, and consists of large olive-green crystalline 
lumps, resembling clay balls. They are very compact and are held 
together by ferric oxide. The specific gravity is 2.91. From the 
analysis the specimen may be fairly classed as a dolomite. 
PER CENT 
SiOg 4.97 
Fe^Og 6.44 
Al^Og 0.00 
CaCOg..... 50.46 
MgCOg 37.82 
99.69 
5 . Specimen from Georgetown, New Mexico . — Dull white 
rhombohedral crystals. The analysis shows the mineral is quite 
a pure calcite rather than a dolomite. The specific gravity is 2.46. 
PER CENT 
SiOg.. ,0.57 
Fe^Og. 0.00 
AlgOg 0.55 
CaCOg 98.32 
MgCOg 0.88 
100.38 
