GUIDE TO THE MINERALOGIC COLLECTIONS 121 



with drusy or velvety surfaces arc of frequent occurrence as 

 well as an earthy variety pink in color. The luster is vitreous to 

 adamantine, pearly on some faces, also dull or earthy. The 

 color is crimson-red to peach-red. 



It is found in Saxony, Baden, Norway and in the United 

 States in Pennsylvania, Nevada and California. 



Wavellite A1 G (0H) 6 (P0 4 ) 4 +9H 2 



Wavellite is a hydrous basic phosphate of aluminium. 



Distinct orthorhombic crystals are rare. The mineral is com- 

 monly found in hemispheric or globular aggregates of radiating 

 fibrous crystals (pi. 37 2 ). Stalactitic forms also occur. The lus- 

 ter is vitreous and the color white, yellow or green, occasionally 

 brown, blue or black. 



It is found in Devonshire, Saxony, Bohemia, Brazil and in 

 Pennsylvania, Arkansas and North Carolina. 



Turquoise A1 2 (0H) 3 P0 4 +H 2 



Turquoise is a hydrous basic phosphate of aluminium with 

 some copper, to which it owes its color. 



It occurs in sky-blue to green nodules, veins or rolled masses 

 with a dull or waxlike luster; also stalactitic or incrusting. 



Turquoise occurs in porphyritic trachyte and in a clay slate 

 which, in the Persian locality, is found penetrated by trachyte. 

 It was formerly extensively mined in Persia; recently, however, 

 important workings in New Mexico have been reopened and are 

 producing rery good material. Localities are also known in 

 Arizona. California, Colorado and Nevada. 



Turquoise is used as a gem. 



Torbernite (copper uranite) Cu(U0 1 ,) 1 ,P 2 s -f8H.,0 



Torbernite is a hydrous phosphate of uranium and copper. 



It occurs in small tabular tetragonal crystals often extremely 

 thin, of a brighl green color and pearly luster. Less frequently 

 it occurs in pyramidal forms or in foliated micaceous aggre 

 gates. 



Ii has been found in Cornwall, Saxony and Bohemia. 



