304 BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



index of 1.780. It is thus grossularite as contrasted with the red- 

 brown andradite from the same mine. 



The last specimen of this lot to be mentioned is from the Copper 

 Boy mine. It consists mainly of reddish black crystals which are 

 dodecahedrons modified by faces of the trapezohedron. These are 

 brilliant in luster and of various sizes from 1 mm. to 2 cm. The 

 black crystals are more porous and lighter colored inside. The outer 

 layers are homogeneous and pale transparent brown, isotropic and 

 have an index estimated at 1.825-1.830. They are laminated but 

 not zoned parallel to the crystal faces. Another specimen from this 

 mine contains brown granular garnet and some crystals up to 5 mm. 

 in size showing the dodecahedron modified by broad faces of the 

 trapezohedron. The garnet is interstitial to coarse columnar epidote. 

 The granular garnet gives a brown powder in the agate mortar and 

 under the microscope is seen to be a mixture containing the pale 

 brown to colorless feebly birefracting garnet with an index above 

 1.82, mixed with quartz and what is probably partly oxidized heden- 

 bergite. 



While it is clear from the preceding descriptions that the garnet 

 from the Seven Devils lime-contact deposits ranges from grossularite 

 to andradite, the greater part of the garnet is well on the andradite 

 side of the half-way composition. 



BEAR LAKE COUNTY 



Garnet occurs in Bear Lake County in NW. }4, sec. 9, T. 8 S., 

 R. 43 E. on Lane's creek, associated with hematite and calcite. 

 The garnet is granular-massive and sugary textured, made up of 

 minute imperfect dodecahedrai crystals. The deposit is probably 

 a metamorphosed limestone. Under the microscope the garnet is 

 pale brown and isotropic with a refractive index moderately above 

 1.820. The calcite and hematite are described under the respective 

 headings elsewhere in this report. 



BLAINE COUNTY 



Lime garnets intermediate between grossularite and andradite 

 have been noted at several places in Blaine County. 



A specimen from the Muldoon district labeled " Country rock," 

 from the Drummond claim, is a chalky looking rock in part white 

 and in part pale brown with a greasy luster. The very pale brown 

 material is massive garnet without any trace of crystalline structure. 

 Under the microscope it is colorless with an average index of refrac- 

 tion of 1.760, which indicates it to be grossularite. The garnet is 

 filled with inclusions. The white material in the specimen is a fine- 

 grained mixture of wollastonite and calcite. 



