groutite

groutite

[′grau̇‚tīt]
(mineralogy)
HMnO2 A mineral of the diaspore group, composed of manganese, hydrogen, and oxygen; it is polymorphous with manganite.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The main minerals of this group are: Brucite, Geothite, Diaspore, Bauxite, Lepidocrocite, Manganite, Groutite, Stainierite and Chalcopanite that this project discusses the diaspore minerals and processing of them from the diaspore minerals.
Groutite, an orthorhombic trimorph of (monoclinic) manganite and feitknechtite, is a rare species known in good specimens chiefly from the Iron Range of Minnesota (in 1980 some superb specimens were collected in the Roberts mine, Cayuna Range, Crow Wing County).
The matrix is massive black manganite, and there are some subhedral white barite crystals, and, on a very few of the specimens, 2-cm metallic black crystals of the rare species groutite. About 30 of the new specimens, ranging from 4 to 10 cm across, were offered at the 2008 Tucson Show (Moore, 2008).
Also, according to Gunnar, free-standing, 2-cm black crystals of the rare species groutite have been spotted on a few specimens from the find.
The vesuvianite is accompanied rarely by transparent, colorless diopside in tabular crystals to more than 1 cm, and by small, black needles of groutite or small prisms of manganite.