THE MINERALS OF IDAHO 285 



ADAMS COUNTY 



Anthophyllite is listed by Livingston and Laney - without further 

 description, as a mineral of the contact metamorphis copper deposits 

 in limestone in the Seven Devils district. 



IDAHO COUNTY 



Anthophyllite occurs in Idaho County 14 miles southeast of 

 Kamiah in large masses similar to those of the asbestus mines of Sail 

 Mountain, Ga. The mineral forms about half a dozen ledges within 

 a few square miles. The largest of these ledges is lenticular in form 

 and is 200 feet long, 40 feet wide and stands 30 feet above the ground. 

 The lenses of anthophyllite apparently represent altered basic intru- 

 sions into the surrounding mica schist. Prospecting has revealed 

 the bottom of some of them so they do not continue to great depth. 

 Several of the masses are known and there are probably others as 

 yet undiscovered, so that a great quantity of the material is avail- 

 able. The anthophyllite forms a mass-fiber asbestus, the fibers of 

 which are arranged in small bundles 5 to 20 mm. in length and 

 generally lying in all directions. Locally the fibers are arranged in 

 radial groups which on cross-fractures yield rosettes sometimes 12 

 cm. in diameter. The fibers are brittle and as asbestus the material 

 is poorer than the poorest chrysotile. The deposits were formerly 

 worked by the Spokane Asbestus Fire Brick Co., who shipped the 

 material to Spokane, where it was sawed into bricks or ground for 

 various purposes. 20 



A large specimen of the Kamiah asbestus was submitted for 

 examination by Edward Sampson, of the United States Geological 

 Survey. This consists of a group of rude prismoidal masses which 

 resemble altered prismatic crystals of some mineral and are in- 

 dividually composed of parallel fibers of anthophyllite. These in- 

 dividual groups of fibers reach an extreme size of 10 by 10 cm. 

 with an average of about 10 cm. in length by 3 cm. in thickness. 

 The specimen is dirty white and somewhat iron-stained but, when 

 fiberized, the fibers are fine, fairly flexible, and white. Selected and 

 pure fibrous material from this specimen was analyzed with the 

 following results: 



» D. C. Livingston and F. B. Laney. Idaho Bur. Mines and Qeol., Bull. 1, p. 62, 1920. 

 2° J. S. Diller. U. S. Geol. Survey .Mineral Resources of United States, 1909, pt. 2, p. 729. 



