Tephroite is a non-metallic manganese silicate mineral with the formula, Mn 2 SiO 4, that is one of the unusual minerals found at the famous Sterling Hill Mine and Franklin, New Jersey, USA.
Tephroite is a non-metallic manganese silicate mineral with the formula, Mn 2 SiO 4. It was first described for an occurence at the Sterling Hill Mine and Franklin, New Jersey, USA.