Graftonite

Graftonite , Heterosite Location: Grafton, Grafton County, New Hampshire, USA. Copyright: © Jeff Weissman / Photographic Guide to Mineral Species

Chemical Formula: (Fe2+,Mn,Ca)3(PO4)2
Name Origin: Named after its locality at Grafton, New Hampshire, USA.
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.

Physical Properties

Cleavage: {010} Perfect
Color: Brown, Pink, Dark brown, Reddish brown.
Density: 3.67 – 3.7, Average = 3.68
Diaphaneity: Translucent
Fracture: Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern.
Hardness: 5 – Apatite
Luminescence: Non-fluorescent.
Luster: Vitreous – Greasy
Streak: pale pink

Photo:

Olgiasca-Malpensata (Piona), Colico, Lecco Province, Lombardy, Italy © G.Fraccaro
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