brucite
noun
bruc·ite
-ˌsīt,
usually -īt + V
plural -s
: a mineral Mg(OH)2 consisting of native magnesium hydroxide occurring in thin pearly folia and in fibrous form (hardness 2.5, specific gravity 2.38–2.40)
Word History
Etymology
Archibald Bruce †1818 American mineralogist + English -ite