Ferro-edenite Locality: Hendersons Quarry, Mt. Ngongotaha, Rotorua, Bay of Plenty, North Island, New Zealand 3 mm Ferro-Edenite crystal. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Ferro-edenite
The iron analogue of edenite — a sodium-calcium amphibole where Fe²⁺ replaces magnesium.
Intro adapted from Wikipedia (CC BY-SA).
Ferro-edenite is an IMA-recognized mineral species in the silicate class, with the chemical formula NaCa₂Fe²⁺₅(Si₇Al)O₂₂(OH)₂.
It crystallizes in the monoclinic crystal system. It is a member of the Amphibole structural group.
Key properties: Mohs hardness 5–6; specific gravity 3.4; [Vitreous.] luster; optically biaxial.
IMA symbol Fed, IMA status: approved, named in 1946.
An early or deuteric phase replacing pyroxene in syenitic ring complexes; from medium-grade metamorphic amphibolites and gneisses; from plutonic igneous rocks.
It is found associated with Pyroxene, ferro-actinolite, monazite, magnetite, fluorite (Tibchi ring complex, Nigeria).
The name refers to its high ferrous iron content and relation to edenite.