crednerite

crednerite

[′kred·nə‚rīt]
(mineralogy)
CuMn2O4 A steel-gray to iron-black foliated mineral consisting of copper, manganese, and oxygen.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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Crednerite is a rare mineral, found for the first time in 1847 at Friedrichroda (Germany) and later in just a few more localities, always in small amounts.
Associations include pink to salmon-orange rhodonite, quartz, calcite, braunite and in places, brownish red pyrobelonite and lustrous black tabular crystals of crednerite. Dark green crystals of tangite in rhodochrosite and quartz veinlets were collected at the Gambatesa mine in 1999.
(1987a) La crednerite di Gambatesa (Val Graveglia).
The finest known examples of a number of supergene copper minerals were found at Bisbee: antlerite, bisbeeite, brochantite, chalcoalumite, claringbullite, conichalcite, crednerite, cuprite, delafossite, graemite, nantokite, paramelaconite, paratacamite, rosasite and spangolite.
The mine is the type locality for the minerals chloroxiphite and diaboleite, and has also produced some of the largest known crystals of hydrocerussite and crednerite. Recently, plattnerite and kentrolite have been identified in old specimens from the locality.
Crednerite has usually been found as fan-like groups and hemispherical masses of thin, bright black plates on nodules of cerussite, hydrocerussite and mendipite in Mn ore.
It is of interest to note that the famous American collector Washington Augustus Roebling (1837-1926) had acquired specimens of mendipite, chloroxiphite, diaboleite and crednerite from the Higher Pitts mine as early as 1894 (in London from the German mineral dealer Oscar Penzig).
The remainder of the specimens from the Higher Pitts mine consists of one or more of the following minerals: cerussite, hydrocerussite, mendipite, crednerite, malachite, chloroxiphite, diaboleite, mimetite and wulfenite (?), together with calcite, hematite, pyrolusite ("wad") and "limonite." The original collection had no catalog, and many of the specimens are without labels.
Specimen Size (cm) Minerals 001-048 [less than]5 Loose masses of cerussite crystals 049-055 - Hydrocerussite, cerussite, "wad" 056-060 [less than]5 Mendipite 061-067 [less than]5 Mendipite, chloroxiphite, diaboleite 068 [less than]5 Mendipite, chloroxiphite, diaboleite 069 [less than]5 Mendipite 070-074 - Hydrocerussite 075-076 - Cerussite 077-078 - Cerussite 079 - Cerussite 080 - Cerussite 081-083 [less than]5 Mendipite 084 [less than]5 Mendipite 085 - Cerussite 086 - Crednerite, diaboleite 087-092 [less than]5 Mendipite, chloroxiphite, diaboleite 093 - Cerussite 094-098 - Cerussite 099-101 [less than]5 Mendipite 102-103 - Cerussite 104 - "Wad" 105 - Cerussite 106 [less than]5 Mendipite 107 - Crednerite 108 - Crednerite (very fine) Only a few of the above specimens are on display.