• WordNet 3.6
    • n pyrolusite a mineral consisting of manganese dioxide; an important source of manganese
    • ***
Webster's Revised Unabridged Dictionary
    • n Pyrolusite (Min) Manganese dioxide, a mineral of an iron-black or dark steel-gray color and metallic luster, usually soft. Pyrolusite parts with its oxygen at a red heat, and is extensively used in discharging the brown and green tints of glass (whence its name).
    • ***
Century Dictionary and Cyclopedia
    • n pyrolusite Native manganese dioxid (MnO2), a common ore of manganese, occurring crystallized and massive, of a gray-color and metallic luster. It parts with a portion of its oxygen at a red heat, and is on this account used to discharge the brown or green tints of glass, whence its name. When crystallized it has often the form of manganite, from which it has been, at least in manycases, derived by alteration. It is very soft, and is readily distinguished by this property from the other form of manganese dioxid, called polianite.
    • ***
Chambers's Twentieth Century Dictionary
    • n Pyrolusite pī-rō-lū′sīt native manganese dioxide.
    • ***


Webster's Revised Unabridged Dictionary
Pyro-, + Gr. to loose, or a loosing


In literature:

How does pyrolusite effect the decolorizing of glass containing iron?
"An Elementary Study of Chemistry" by William McPherson
Generally resembles pyrolusite, but is distinguished from it by its superior hardness.
"The Elements of Blowpipe Analysis" by Frederick Hutton Getman
Appended are two analyses of pyrolusite containing sesquioxide of iron.
"British Manufacturing Industries" by L. Arnoux
Manganese dioxide (pyrolusite) 40 parts.
"Electric Bells and All About Them" by S. R. Bottone