Voi,. 7, 1921 
MINERALOGY: W. LINDGREN 
249 
4 Conner, Amer. J. Math., 37, 1915 (29). 
5 Schottky, Acta Math., 27, 1903 (235). 
6 Coble, Amer. J. Math., 41, 1919 (243). 
7 Wirtinger, Math. Ann., 27, 1892 (261); Untersuchung iiber Thetafunctioners, 
Leipzig (1895). 
8 Coble, Amer. J. Math., 32, 1910 (333). 
9 Shenton, Ibid., 372 1915 (247). 
10 Cf. Coble, /. c, p. 352. 
MEL AN 0 VANADI TE, A NEW MINERAL FROM 
MINA RAGRA, PASCO, PERU 
By WaldEmar IjndgrEn 
Department of Mining, Metallurgy and Geology, Massachusetts Institute 
of Technology 
Communicated, March 9, 1921 
Late in 1920 Mr. W. Spencer Hutchinson, Consulting Engineer for the 
Vanadium Company of America, brought to my attention three specimens 
of a mineral collected by him at Mina Ragra, Peru. He suspected that it 
was a new mineral, and this opinion was proved correct by chemical and 
optical examination. The formula is 2CaO. 3V2O5.2V2O4 and I wish to pro- 
pose for it the name of Melanovanadite, in allusion to it being practically 
the only vanadium mineral of a deep black color. 1 
The mineral occurs in acicular bunches on black brecciated shale, the 
individual crystals being at most 3 mm. long. 
The greater thickness of the needles is about 0.5 mm. ranging down to 
0.1 and 0.01 mm. The color is black, luster almost submetallic, streak 
very dark reddish brown. The hardness is 2.5 the specific gravity 3.477 
at 15° C. The habit of the crystals is prismatic, parallel to c, with mon- 
oclinic symmetry. The principal faces consist of a flat, striated prism, 
the longer diagonal being parallel to the b axis, minor pinacoidal faces, and 
usually well developed terminal faces of pyramids and smaller domes. 
The crystals have a perfect cleavage parallel to (010). 
Under the microscope the crystals remain black except in very thin 
prisms which are translucent with brown color. 
Flat cleavage pieces parallel to the clinopinacoid only become trans- 
lucent when the thickness is about 0.003 mm. and then show maximum ex- 
tinction of about 15 °. Resting on the prism (100) the crystals become 
brown translucent with a thickness of about 0.03 mm. and then show lower 
extinctions of 12° to 13°, while these resting more nearly on the orthopin- 
acoid extinguish at lower angles. The perfect cleavage being perpen- 
1 The ending "vanadite" is an obsolete form of "vanadinite," but there can scarcely 
be any objection to using this form in the present case. 
