THE MINERALS OF IDAHO 183 



summer and fall of 1891 amounted to over $5,000. The material 

 is stated to have been fine, in many respects equal to the best material 

 from the Hungarian or Australian mines. A gem, weighing 3^2 

 carats, from this district was held at the rather extravagant figure of 

 $500, partly perhaps on account of its American origin, and a rough 

 mass of 2 ounces for $1,200. The deposits apparently were worked 

 mainly on the Washington side of the line, but it is reported that 

 in that year two companies were working on the Idaho side in Latah 

 County. 78 



It is reported that, in 1893, the North America Gem and Opal 

 Mining Co., which operated the mines at Moscow, did no work 

 owing to litigation. 79 There is little further mention of any work 

 done on these deposits until 1904 when the mines were reported 

 reopened. 80 No subsequent production has been reported, although 

 it was later stated that in Latah and adjoining counties precious 

 opal of the finest quality that has been found on this continent 

 occurs near Salmon River as nodules in a very hard trachytic rock 

 resembling the rock in which opal is found in Hungary. A single 

 stone from this locality was worth $1,000. 81 A report based on the 

 Washington side of the area states that the country is rolling meadow 

 land adapted to the growing of wheat and that relatively little 

 attention was paid to the possibilities of gem mining. The dumps 

 contain piles of vesicular basalt, which is evidently part of a flow 

 covering large areas in this region. Some of the rock is partly 

 weathered and of a gray color but the fresh rock is grayish black 

 and hard. In places hyaline opal occurs, filling vesicles and seams 

 in the rock ; and in places patches of precious opal can be found by 

 breaking considerable rock. In places precious opal was found 

 thickly scattered through the rock and some very fine gem opal 

 was obtained. 82 



Some very good specimens of dark gray opalized wood have been 

 seen from near Kendrick. 



LEMHI COUNTY 



Homogeneous masses of flinty common opal of various colors, 

 including yellow, flesh pink, and black have been sent to the National 

 Museum from May, a post office in Lemhi County, Idaho. 



Opals were discovered in Lemhi County in 1902 on Panther Creek 

 on the west side of the valley about 6 miles below its head and at an 

 altitude of 7,000 feet. Here a large dike of porphyry runs parallel 

 to the creek for nearly a mile and a half, forming a ledge partly 



M George F. Kunz. U. S. Geol. Survey, Mineral Resources of United States, 1892, p. 776. * 



79 George F. Kunz. U. S. Geol. Survey, Mineral Resources of United States, 1893, p. 698. 



80 George F. Kunz. U. S. Geol. Survey, Mineral Resources, 1904, p. 956. 

 » George F. Kunz. Ann. N. Y. Acad. Sci., vol. 21, pp. 214-215, 1912. 



" Douglas B. Sterrett. U. S. Geol. Survey, Mineral Resources, 1910, pt. 2, p .874. 



