The edenite Mineral Group
Edenite is a member of the extended Hornblende group. There are
several variations of Edenite with different elemental
substitutions. Some of these are recognized as individual minerals,
thereby making Edenite a mineral group, with Edenite the
dominating member. Edenite is named after the hamlet of Edenville, New York, the type locality where this mineral was first described.
Light green, dark green, greenish-gray, gray, black. Rarely white, tan, or yellow.
Edenite is the name of an individual mineral, as well as group name
for a few similar Edenite-related minerals with slight variations
elements in their chemical formula. Edenite is the
magenesium and hydroxyl-rich form of this series, and the other forms the recognized by the IMA as individual minerals are listed below.
Variety of Edenite where iron replaces the magnesium content. Ferro-edenite is recognized by the IMA as a distinct mineral species with the following chemical formula: NaCa2Fe2+5Si7O22(OH)2
Variety of Edenite where fluorine replaces some the hydroxyl content.
Fluoro-edenite is recognized by the IMA as a distinct mineral species
with the following chemical formula: NaCa2Mg5Si7O22(F,OH)2
Edenite is probably more common than perceived, and can sometimes be perceived as Hornblende and not further identified. Dark crystal groups of Edenite were found in the Franklin marble at Amity and Edenville, Orange Co., New York, and across the border in Franklin and Ogdensburg, Sussex Co., New Jersey. In Canada, large crystals have come from several localities in Wilberforce, Monmouth Township, Haliburton Co., Ontario. Small crystals were also found in Mont Saint Hilaire, Quebec.