seybertite

noun

sey·​bert·​ite

ˈsībə(r)tˌīt

plural -s

: 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)

Word History

Etymology

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

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