296 A. K Chester— Sepiolite from Utah. 



founded. Its composition, moreover, is identical with that 

 obtained by Petersen for the variscite of Breithaupt, and 

 closely corresponds to that of the i <f Damour. 



Analysis 1. bel.uv. is h } Petersen f.Ta .rb. Mm.. 1871, 357) of 

 variscite from Messbach, in Saxon Voigtland ; and analysis 2, 

 one given by Damour (after the deduction of 2-10 p. c. of sand), 

 ofcailais: 



1 2 



Phosphoric acid 44-05 43-31 



Alumina 81*25 30-09 



Iron sesquioxide * 1*21 1-86 



Magnesia 041 



Lime 0-18 0'70 



Total, 99-95 100-00 



1 With Cr 2 3 and FeO. 



Both of these analyses agree closely with the formula given, 

 A1,0„ P.,0 5 +4H„6, which requires: phosphoric acid 44-80, 

 alumina 3249, water 22-71 = 100. The mineral from Arkansas 

 trite of Damour should consequently be in- 

 cluded under the name variscite, given in 1837 by Breithaupt. 



The mineral occurs in crystalline crusts on quartz; also 

 rarely in distinct crystals of very small size. These belong to 

 the orthorhombic system, showing prismatic and basal planes. 

 The crust often presents a semi-globular form with a radiated 

 structure. It also occurs amorphous and disseminated through 

 quartz. The colors observed are deep emerald-green, though 

 all shades of bluish green to almost colorless. Some crystals 

 are dark in the middle, and light at both ends. It is trans- 

 parent to * -.and has a hardness of about 4. 

 Before the blowpipe it becomes opaque, friable, and of a deep 

 purple when hot, lighter purple when cold. In the glass tube 

 yields much water and changes in color as above. 



Chemical Laboratory, Hamilton College, Clinton, N. Y., Feb. 12. 



Some years since I obtained, while visiting a silver mine m 

 Utah, specimens of a fibrous mineral 



proves to have the composition of sepiolite. It occurs in a 

 seam about two inches in thickness cutting across the rock 

 "strata and vein at nearly right angles. The following 

 give the composition of two varieties, one of which 

 and the other bluish-green ; 1 is the mean of four analyses of 



