Penfield and Foote — Bixbyite, a new Mineral, etc. 105 



Art. XIII. — On Bixbyite, a new Mineral, and Notes on the 

 Associated Topaz ; by S. L. Penfield and JEL W. Foote. 



Bixbyite. — The mineral to be described in the present article 

 was sent to us for identification by Mr. Maynard Bixby of Salt 

 Lake City, Utah. Concerning its occurrence we are informed 

 that the mineral is found very sparingly in one or two small 

 areas on the edge of the desert about thirty-five miles south- 

 west of Simpson, Utah. The crystals are implanted upon 

 topaz and decomposed garnet and rhyolite and have evidently 

 been formed by fumarole action. 



The mineral crystallizes in the isometric system, usually in 

 cubes, some of which measure over 5 mm on an edge. These 

 are occasionally modified by the trapezohedron, 211, and on one 

 small specimen the cubes and trapezohedrons are developed 

 with almost ideal symmetry as shown in 

 fig. 1. When measured on the goniome- 

 ter the crystals gave fairly good reflec- 

 tions of the signal and 211 /\ 112 was 

 found to be 33° 40' ; calculated 33° 33^. 

 The mineral breaks with an irregular frac- 

 ture, and on one or two specimens traces 

 of octahedral cleavage were observed. 

 The color is brilliant-black with metallic 

 luster, and the streak is black. The hard- 

 ness is 6 to 6*5. The specific gravity of the 



material used for the quantitative analysis was taken on a chem- 

 ical balance and found to be 4*945. The mineral fuses before 

 the blowpipe at about 4 and becomes magnetic. When very 

 finely powdered, it dissolves with some difficulty in hydro- 

 chloric acid with evolution of chlorine. 



Method of Analysis. — The material for analysis was sepa- 

 rated in a nearly pure condition by the thallium-silver nitrate 

 mixture. The mineral was treated with strong hydrochloric 

 acid in a flask connected with a condenser, and the chlorine 

 liberated was distilled over into a solution of potassium iodide. 

 Free iodine was then determined volumetrically with standard 

 thiosulphate and iodine solutions, from which the amount of 

 available oxygen was calculated. After filtering off a small 

 amount of insoluble material, iron, aluminium and titanium 

 were separated from manganese and magnesium by the basic 

 acetate method. The three oxides were weighed together, iron 

 was then determined by titration with permanganate solution 

 and titanium was twice precipitated by boiling the nearly neu- 

 tral dilute sulphate solution for two hours in the presence of 



