Tephroite

Tephroite is a non-metallic manganese silicate mineral with the formula, Mn₂SiO₄, that is one of the unusual minerals found at the famous mines of Sterling Hill and Franklin, New Jersey, USA. It can also be found in England and Sweden.

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Tephroite has a hardness of 6 and a specific gravity of approximately 4.1, which is heavy for non-metallic minerals. Its name comes from the Greek tephros - "ash gray"- for its color. It can also be found olive-green, greenish-blue, pink or brown.

References

• Webmineral data
• Mineral galleries
• Mineral Data Publishing