Ilvaite is a sorosilicate of

iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

and

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

with formula: CaFe²⁺₂Fe³⁺Si₂O₇O(OH). Both

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

and

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

substitute in the structure. Ilvaite crystallizes in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

system in black prismatic crystals and columnar masses. It is black to brownish black to gray and opaque. It has a

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by t ...

of 5.5 to 6 and a

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...

of 3.8 to 4.1. Ilvaite is structurally related to lawsonite. It occurs in contact metamorphic rocks and

skarn Skarns or tactites are hard, coarse-grained metamorphic rocks that form by a process called metasomatism. Skarns tend to be rich in calcium-magnesium-iron-manganese-aluminium silicate minerals, which are also referred to as calc-silicate mineral ...

ore deposits. It also occurs less commonly in syenites. Ilvaite was first described in 1811 on the island of

Elba Elba ( it, isola d'Elba, ; la, Ilva) is a Mediterranean island in Tuscany, Italy, from the coastal town of Piombino on the Italian mainland, and the largest island of the Tuscan Archipelago. It is also part of the Arcipelago Toscano Nationa ...

and the name ilvaite from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

name ''ilva'' of the island. Sometimes referred to as yenite.

References

WebmineralMindat w/ locationsMineralienatlas
* Calcium minerals Iron(II,III) minerals Sorosilicates Monoclinic minerals Minerals in space group 14 {{silicate-mineral-stub