sey·​bert·​ite | \ ˈsībə(r)tˌīt\
plural -s

Definition of seybertite

: a basic aluminosilicate Ca(Mg,Al)3(Al,Si)4(O,OH)12 of the clintonite group consisting of calcium, magnesium, and aluminum, occurring in monoclinic crystals and foliated masses and having a reddish brown, copper red, or yellowish color and submetallic luster (hardness 4–5, specific gravity 3–3.1)

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History and Etymology for seybertite

French, from Henry Seybert †1883 American mineralogist + French -ite

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