IOWA ACADEMY OF SCIENCES. 
175 
TOPAZ CRYSTALS OF THOMAS MOUNTAIN, UTAH. 
BY ARTHUR J. JONES. 
In the summer of 1891 it was the privilege of the writer to 
visit what is known as Topaz Mountain in southern Utah. It 
is about thirty -five miles south of the northern end of the Hug- 
way Mountains, called by Simpson the Thomas Range, twenty- 
five miles northwest of Deseret, forty miles north of Sevier 
Lake, and about the same distance west of Eureka, Utah. 
This locality was discovered by Henry Englemann, geologist 
of Capt. Simpson’s expedition across Utah in 1859. Owing to 
inaccuracies in the description of the place it was lost sight of 
for nearly ten years but was at last re-discovered and has since 
been visited constantly by tourists. Very few accounts of the 
locality have, however, appeared in print. 
Englemann* describes the crystals found here as follows; 
‘‘Perfectly colorless and transparent and of great beauty 
and luster. Degree of hardness==8. Before the blowpipe they 
proved infusible and when strongly heated they were covered 
with small blisters, but did not show any change of color. They 
exhibit reactions of fluorine, alumina and silex.” 
Prof. J. E. Clayton of Salt Lake City, visited this place in 
1884 and collected many very beautiful crystals, some of which 
he sent to Whitman Cross for examination. These were soon 
afterward described by the latter f in connection with similar 
crystals from Colorado. 
Other accounts of the same occurrence have been given from 
the information furnished by Prof. Clayton, by Mr. G. P. Kunz. J 
In the book first mentioned Mr. Kunz describes the topaz as 
‘ ‘ the most beautiful and brilliant crystals known to occur in 
* Exploration across the Great Basin of Utah, Simpson, 1859. p. 325. 
t Am. Jour. Sci., (3), XXXI, 433. 1886. 
$Gems and Precious Stones, p. 67. New York, 1892, U. S. Geol. Surv., Mineral 
Resources, 1883-1884, p. 738. 1885. U. S. Geol. Surv., Mineral Resources, 1892, p. 
764. 1893. 
