HESS AND schaller: pintadoite and uvanite 577 



found. Some of the minerals are so mixed with impurities and 

 are in such fine particles that mechanical separation is practically- 

 impossible and their optical characteristics can be determined 

 only very imperfectly. 



Fairly satisfactory determinations have been made of two of 

 these minerals which have proved to be new species and it is the 

 object of this paper to place them on recprd. Like most of the 

 uranium and vanadium minerals of this field, they are highly 

 oxidized and are hydrous. One, a green hydrous calcium vana- 

 date, has been called pintadoite (peen-ta '-do-ite) from Canyon 

 Pintado, in which it is found. The other, a hydrous uranium 

 vanadate has been named uvanite (yu'-van-ite) , a word derived 

 from the words ?/ranium and ?;anadium. 



Pintadoite forms a thin green efflorescence upon the face of 

 cliffs of sandstone belonging to the McElmo. formation, which 

 are protected by overhanging ledges from the weather. It forms 

 circular or rounded patches like the lichens common on rocks, 

 and though in general of a rich dark green color, many patches 

 are in part lighter green and contain a little yellowish or salmon 

 colored material, which may be pascoite. The contrast with the 

 creamy or nearly white sandstones is striking and very pretty. 

 Being a thin efflorescence it is naturally mixed with gypsum, 

 quartz and other minerals of the sandstone. The specimen an- 

 alyzed is from the Frisco No. 2 claim, on the north side of Caiion 

 Pintado,^ San Juan County, about 15 miles by road, northeast of 

 Monticello, Utah, and is the dark green material. Pintadoite 

 has also been found at numerous other places in southeastern 

 Utah. 



The mineral shows no crj^stal boundaries when examined 

 microscopically, is slightly pleochroic in yellow-green, and has a 

 moderate to high birefringence. It dissolves slowly in cold water 

 from which it recrystallizes in twinned, lath-shaped crystals. 



The analysis, by W. T. Schaller, after deducting insoluble 

 gangue (sandstone), soluble gypsum, and reduction to 100 per 

 cent, is given below: 



1 Locally known as East Canyon. 



