[pahy-ruh-loo-sahyt, pahy-rol-yuh-sahyt]
  1. a common mineral, manganese dioxide, MnO2, the principal ore of manganese, used in various manufactures, as a decolorizer of brown or green tints in glass, and as a depolarizer in dry-cell batteries.

Origin of pyrolusite

1820–30; pyro- + Greek loûs(is) washing + -ite1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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Historical Examples of pyrolusite

British Dictionary definitions for pyrolusite


  1. a blackish fibrous or soft powdery mineral consisting of manganese dioxide in tetragonal crystalline form. It occurs in association with other manganese ores and is an important source of manganese. Formula: MnO 2

Word Origin for pyrolusite

C19: from pyro- + Greek lousis a washing + -ite 1, from its use in purifying glass
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for pyrolusite

"manganese dioxide," 1828, the name given in Roman times, when it was used, in a heated state, to de-colorize glass, from Greek elements pyro- "by heat, by fire" (see pyro-) + lysis "a loosening" (see lose).

Online Etymology Dictionary, © 2010 Douglas Harper