NO. 1867. CRYSTALLIZED VARI8CITE FROM UTAH.— SGRALLER. 429 



CHEMICAL COMPOSITION. 



GENERAL PROPERTIES. 



The mineral is infusible before the blowpipe, but readily changes 

 its color in a striking way. The deep emerald green changes to a 

 deep lavender and the crystals take on a much more brilliant luster. 

 As quantitative analyses showed, all the water of the mineral is 

 given off during the change of color and the lavender variscite is 

 anhydrous. Chester ^ mentions a similar change in color for the 

 variscite from Arkansas, but his results seem to have been generally 

 overlooked. In describing the properties of the crystallized variscite 

 Chester says : 



The colors observed are deep emerald green. * * * Before the blowpipe it 

 becomes opaque, friable, and of a deep pm'ple when hot, lighter piu-ple when cold. 

 In the glass tube yields much water and changes in color as above. 



The density of the green mineral was found to be 2.54. 



The powdered mineral is insoluble in boiling hydrochloric acid, 

 but after dehydration and change in color it readily dissolves in acids. 

 The striking color changes observed in the mineral suggested testing 

 especially for such rarer elements as had a strong chromatic effect. 

 It was found that chromium and vanadium were present in small 

 amounts, and a trace of iron was also determined. 



CHEMICAL ANALYSIS. 



The results of the quantitative analysis and the ratios deduced 

 therefrom are here given. 



Analysis and ratios of crystallized variscite from Lucin, Utah. 



The ratios agree very well with the formula AI2O3.P2O5.4H2O, thus 

 comparing with strengite (Fe2O3.P2O5.4H2O) and not with phos- 

 phosiderite (Fe203.P20g. 3^1120) even though the crystals of variscite 

 are much closer in angular values to those of phosphosiderite than to 

 those of strengite. 



1 Chester, Albert H. On the identity of the so-called peganite of Arkansas with the variscite of Breit- 

 haupt and Callainite of Damour. Amer. Journ. Sci., 3 ser., vol. 13, 1877, p. 295. 



