Habit botryoidal

Pitchblende [Named after pitch and blende] U3O, M = 841.995 84.80 wt.% U 15.20 wt.% 0 Oxides and hydroxydes Amorphous Isotropic R = 16.0% 3-5 (HV 673- 803) 8000- 9000 Habit amorphous botryoidal mass. Color black. Luster submetaUic. Contains up to 20 wL% FbO from decaying. 

Psilomelane (syn., Romanechite) [from Greek, psilos, smooth, and melanos, black, owing to the common smooth sur ce of the concretions from Roman che, Sadne-et-Loire, France] (ICSD 202692 and PDF 42-618) BaMn"Mn",0 (OH), Af = 955.74568 Coordinence Ba(lO), Mn(6) (Oxides and hydroxides) Monodinic a = 1392.9 pm b = 284.6 pm c= 967.8 pm 92.65 (2=2) P.a2/m S.G. C2/m Biaxial (aa.) R = 24.1-28.8% 5-6 (HV 503- 627) 3950- 4710 (4740) Habit massive, reniform, botryoidal, earthy, fibrous, dendritic. Color dark black to dark steel gray. Luster submetaUic to dulL Diaphaneity opaque. Streak brown to black. Qea ige none. Fracture uneven to conchoidal, brittle. Occurrence associated with cryptomelane. Note wad is a common name for a low hardness varieties, while manganomelane describes high density varieties (i.e., above 3000 kg.m ). 

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