ASSOCIATED MINERALS 191 



atecl parallel to the dodecahedral faces and the stri* run also parallel to 

 the light brown streaks. 



One garnet crystal was found that has a topaz grown into it in sixch a 

 way as to show that the garnet had partially grown around the topaz. 

 This indicates that the topaz had formed before the garnet was com- 

 pleted. 



In this connection it may be noted that the writer, a week or so after 

 leaving the Thomas range, ran across another occurrence of garnet in 

 lithophysal cavities in rhyolite. This was in Lincoln county, Nevada, a 

 few miles west of the Utah line and near the new gold camp called Gold 

 Spring. This new camp is about 12 miles from the town of Modena, 

 Utah. The rhyolite forms a dike that rises conspicuously a hundred feet 

 or so above the heavily wooded hillside. The dark reddish brown garnets 

 have the customary trapezohedral form and vary from one-quarter to 

 three-quarters of an inch in diameter. 



BIXBYITE 



In a paper entitled "On bixbyite, a new mineral, and notes on the 

 associated topaz," Penfield and Foote, in 1897,^- described the mineral 

 which they named bixbyite as an oxide of manganese and iron, 

 FeO.MnOo, and as occurring implanted on topaz crystals, and as having 

 isometric forms, chiefly the cube. The bixbyite crystals are descrilx'd as 

 occurring with both transparent and opaque topaz; and, further identify- 

 ing the opaque crystals of topaz with those described in this paper, the 

 authors add : 



"The opaque crystals, as shown by microscopic examination, are not pseudo- 

 morphs, but consist of fresh unaltered topaz containing minute quartz crys- 

 tals, which evidently have been included during crystallization." 



As the writer was not aware of the fact that the new mineral, bixbyite, 

 was likely to be found at Topaz mountain, no search was made for it and 

 none was noted; but, on looking over the material collected, it has been 

 found adhering to rough opaque topaz. There is every reason to believe, 

 therefore, that it must also occur in the lithophysse proper. 



Conclusion 



In conclusion it may be well to state that the notion that prevails in 

 some quarters that the topaz crystals may be fairly scooped up on the 



^ American Journal of Science, 4th series, vol. iv, 1S97, pp. 105-108. 



