Ilvaite n. : A silicate of iron and lime occurring in black prismatic crystals and columnar masses.

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Taxonomy
Ilvaite, free encyclopedia, island of Elba, search, scale, formula, CaFe2, substitute, prismatic crystals, columnar, masses, brownish black, opaque, ore deposits, ilva, Iron minerals, Personal tools, Interaction.

Defination from the web:
Ilvaite crystallizes in the orthorhombic system in black prismatic crystals and columnar masses. It is black to brownish black to gray and opaque. ... Ilvaite is structurally related to lawsonite. It occurs in contact metamorphic rocks and skarn ore deposits. It also occurs less ...