Category Phosphate minerals Strunz classification 8.AB.20 Space group P21/c | Formula
(repeating unit) (Fe,Mn,Ca)3(PO4)2 Crystal system Monoclinic | |
 | ||
Crystal class Prismatic (2/m)
(same H-M symbol) | ||
Graftonite is an iron(II), manganese, calcium phosphate mineral with formula: (Fe2+,Mn,Ca)3(PO4)2. It forms lamellar to granular translucent brown to red-brown to pink monoclinic prismatic crystals. It has a vitreous luster with a Mohs hardness of 5 and a specific gravity of 3.67 to 3.7.
It was first described from its type locality of Melvin Mountain in the town of Grafton, in Grafton County, New Hampshire.
References
Graftonite Wikipedia(Text) CC BY-SA