Kentrolite is an orthorhombic, lead manganese silicate named in 1880 by Alexis Damour and Gerhard von Rath from the Greek word for "thorn" or "spike", in reference to its habit. It forms dark red-brown to red-black, vitreous, translucent, minute, short prismatic crystals in sheaf-like aggregates. Kentrolite is associated with braunite, richterite, and barite in the Fe-Mn deposits at the type locality: Langban, Jakobsberg, Varmland, Sweden with calcite, willemite, and franklinite. It is also found at several other localities in this district. Other notable localities include: Franklin mine, Franklin, Sussex Co., New Jersey; Bona de Padru, near Ozieri, Sardinia, Italy; Higher Pitts Farm, Priddy, Somerset, England, UK; Kombat mine, Kombat, Grootfontein district, Otjozondjupa Region, Namibia; Wessels mine, near Kuruman, Kalahari Manganese Field, Northern Cape Province, South Africa. It is also found in veinlets cutting franklinite ore in bedded manganese deposits at Ushkatyn, Atsui area, Kazakhstan.
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