Hillebrand and Merwin — Calciovolborthite (f ) 445 



mineral called by it differs fundamentally from volborthotite, 

 although the latter is also a copper vanadate. It is very unfor- 

 tunate that a name so inappropriate and misleading should 

 have been given. 



In 1908 J. Antipoff * gave in Russian a very unsatisfactory 

 description of a new occurrence of uranium and vanadium 

 minerals at Tuya Muyun, a hill in the Alai Mountains, in the 

 province of Ferghana, Russian Turkestan. 



One of the minerals mentioned is regarded as allied to vol- 

 borthite, and is called Turkestan volborthite, although it 

 approaches calciovolborthite far more closely in composition, 

 as the figures below show : 



V 2 6 41-03 



Mo0 3 _ -23 



CuO 29-45 



CaO ._ 20-40 



Fe 2 3 



Al 2 3 f 280 



Si0 2 1-10 



H 2 _. _ 4-55 



99-56 



The formula assigned by the author is 



(V0 4 ) 4 Cu 3 Ca 3 .2H 2 0. 



Later, in 1909, K. Nenadkevitchf described, as the predom- 

 inating vanadium mineral at the same locality, another vana- 

 date under the name turanite, and assigned to it the formula 

 5CuO . Y 2 5 . 2H 2 0. It is said to occur as compact or radiating, 

 olive-green, spherical concretions and kidney-like crusts in cav- 

 ities of malachite and ore-bearing limestone. 



Bureau of Standards and Geophysical Labo- 

 ratory of the Carnegie Institution 

 Washington, D. C, Feb. 



* Gornii Journal, iv, 255-267, 1908. Through Neues Jahrb. fur Min., etc., 

 ii, p. 37, ref., 1909. 



f Bull. Acad. Sci., St. Petersburg, 1909, 185-186. 



