 |
|
|
Tephroite is uncommon member of the Olivine group. It is the manganese counterpart of Forsterite, and forms a series with Forsterite. Tephroite gets it name from the Greek word "tephros", meaning ash-colored, referring to its ash-gray color habit. |
|
|
Chemical Formula |
Mn2SiO4 |
|
Composition |
Manganese silicate, sometimes with some magnesium and zinc. Forms a series with Forsterite. |
| Variable Formula |
(Mn,Mg,Zn)2SiO4 |
|
Color |
Gray, grayish-green, olive-green, brown, reddish-brown, pink |
|
Streak |
Light gray |
|
Hardness |
6 |
|
Crystal System |
Orthorhombic |
Crystal Forms
and Aggregates |
As rounded and fractured crystals, usually short and prismatic, but occasionally elongated. Also occurs grainy, massive, and in large cleavage fragments. |
|
Transparency |
Translucent. Rarely transparent. |
|
Specific Gravity |
4.0 - 4.1 |
|
Luster |
Vitreous, greasy, waxy |
|
Cleavage |
2,1 ; 3,1- forming a 90º angle |
|
Fracture |
Conchoidal to uneven |
|
Tenacity |
Brittle |
|
In Group |
Silicates; Nesosilicates |
|
Striking Features |
Cleavage angles, color, and hardness. |
| Environment |
In manganese-rich metamorphic deposits. |
| Rock Type |
Metamorphic |
|
Popularity (1-4)
|
3 |
|
Prevalence (1-3)
|
3 |
|
Demand (1-3) |
3 |
|
|
Worldwide localities for Tephroite include Broken Hill, New South Wales, Australia; the Wessels Mine, Hotazel, Kalahari manganese fields, South Africa; and Langban, Sweden. In the U.S., the most well-known Tephroite is from Franklin, Ogdensburg, and Sparta, all in Sussex Co., New Jersey. Tephroite is also found in the Jail Hill Quarry, Haddam, Middlesex Co., Connecticut.
|
Willemite - Different cleavage, fluoresces bright green.
Rhodonite - Usually pinker in color.
|
|
|
|
|
|
|
|
Have a question about Tephroite? Visit our Q&A Community and ask the experts!
|
|
|
|
Let us know how we can update this page
(Click for more details)
|
|
We strive for accurate content and locality information. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site. If you are requesting a locality be added, please only include significant locality occurences for the mineral.
|
 |
| |
 |
|
|
|
|
|
