Eaki.e.] 



Mineralogical Notes. 



319 



An analysis of the mineral showed the composition: — 



Per cent. 



SiO, 36.7 1 



A1.A 0.17 



CaO 33-83 



B. 2 O s 22.1 1 



H 2 ignition 6.52 



99-34 



The mineral was dissolved in hydrochloric acid, and then 

 evaporated several times to dryness, on the water bath, with the 

 addition of methylalcohol to expel the boron, and the silica and 

 bases were then determined. The boric acid was determined by 

 distillation with nitric acid, and methylalcohol and the distillate then 

 titrated. All the water was expelled at a low red heat. 



II. ZIRCON CRYSTALS FROM SISKIYOU COUNTY, CALIFORNIA. 



Several small zircon crystals obtained from the panning of gold 

 bearing black sands, about forty miles from Fort Jones, Siskiyou 

 Co., Cal., were sent to the writer by Dr. C. S. Cowan, for identifi- 

 cation. The crystals are transparent, and vary from very pale to 

 deep wine in color, resembling quite strongly wine-colored topaz 

 crystals in general appearance. They range from two to five milli- 

 meters in size and are about as long as they are broad. The faces 

 are exceptionally bright and perfect, and yield the most perfect 

 reflections. 



The forms observed are: — 



tf(ioo) e{\o\) 

 m{\\6) X 111 ) 

 .r( 3 n) 5(511) 



The measurements made with the reflecting goniometer were as 

 follows: — 



Measured. Calculated. 



a: x=(ioo): (311) 31° 43' 3i°43' 



a : z = (ioo) : (5 n) 20 21' 20 25' 



