THE MINERALS OF IDAHO 319 



CLEARWATER COUNTY 



Placer concentrates from the Pierce district contain zircon of the 

 usual type but not abundantly. Scarce highly perfect transparent 

 crystals occur with ilmenite and garnet in a sand from Rhodes Creek, 

 Pierce City, and similar crystals are decidedly rare in concentrates 

 labeled Pierce City and Cow Creek-Pierce district. Monazite is 

 about as abundant as the zircon in these sands which consist largely 

 of ilmenite and rose red garnet. 



ELMORE COUNTY 



A concentrate marked "Zircon, Big Rock placer claim, Wood 

 Creek, Elmore County," consists predominantly of minute colorless 

 zircon crystals. 



IDAHO COUNTY 



Zircon is reported to be very abundant in some of the placers of 

 the Warren and Florence districts where the heavy residues of the 

 sluices are called "white sand" because of its predominance. 41 



Not many samples from this county have been examined. Two 

 separation products labeled "Zircon," one from Salmon River and 

 the other from the Baboon placer, Elk City, consist predominantly 

 of minute colorless zircon crystals of the usual types. 



MINIDOKA COUNTY 



Zircon is very rare in concentrates from Snake River sands from 



Minidoka, Wapi, and 8 miles east of Wapi, which consist largely of 



augite and ilmenite with less garnet and olivine. A few crystals of 



orange red color and the habit illustrated in Figure 91 were seen in 



a sand from Minidoka and also some which are long prismatic with 



the length 10 to 20 times the diameter. These are pale pink in color 



and show only the unit prism m(110) and the pyramid p(lll), as 



shown in Figure 89. 



TOPAZ (397) 



Aluminum fluosilicate, Al(F,OH) 2 . Orthorhombic. 



AlSi0 4 . 



The few occurrences of topaz, well known as a gem stone, which 

 have thus far been reported in Idaho are as follows : 



CASSIA COUNTY 



White topaz was reported to have been found at City of Rocks, 

 5 miles north of Moulton, Cassia County, in 1919. 42 This material 

 was not topaz, as shown later, but colorless quartz crystals. 43 



« Waldemar Lindgren. U. S. Qeol. Survey, 20th Ann. Rept., pt. 3, p. 234, 1900. 

 » U. S. Qeol. Survey, Mineral Resources of United States for 1919, pt. 2, p. 179. 

 < 3 Miles E. North, Reno, Nev. Personal letter, 1920. 



