Friedelite (brown), rhodonite (pink) and manganese oxides (black). Serrana mine, El Molar (Tarragona), Spain. 5 cm. Coll, and photo Miguel Calvo. — Photo: Miguel Calvo · CC BY 4.0
Friedelite
A manganese-rich member of the pyrosmalite group, named for chemist Charles Friedel.
Intro adapted from Wikipedia (CC BY-SA).
Friedelite is an IMA-recognized mineral species in the silicate class, with the chemical formula Mn²⁺₈Si₆O₁₅(OH)₁₀.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Pyrosmalite, Clay structural group.
Key properties: Mohs hardness 4–5; specific gravity 3.04–3.06; typically pink or red or brown; Pale rose streak; Vitreous, pearly on basal plane luster.
IMA symbol Fdl, grandfathered status — known before the IMA’s founding, named in 1876.
Found in metamorphosed Mn-Fe deposits.
It is found associated with Rhodochrosite, alabandite (Adervielle, France); franklinite, willemite, calcite, rhodochrosite, barite, chlorite, sphalerite (Franklin, New Jersey, USA).
The name refers to the noted French chemist and mineralogist, Charles Friedel (1832–1899).
Collections: Collector Favorites, Rare & Remarkable.