The colors are rich and lively, but the mineral is too soft for wear. Hureaulite is a collector gem and is very rare even in cabochon form.
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|Crystallography||Monoclinic. Crystals prismatic up to 3 cm, tabular; massive; compact.|
|Colors||Pale rose, violet-rose, yellowish, red-orange, orange-red, brownish orange, yellowish to reddish brown, gray, colorless.|
|Luster||Vitreous to greasy.|
|Cleavage||Good 1 direction. Fracture uneven. Brittle.|
|Stone Sizes||Massive material suited only for cabochons. No faceted gems have been reported to date, but facetable material likely exists and one day will be cut.|
|Formula||Mn5(PO4)2[(PO3)(OH)]2 · 4H20.|
|Pleochroism||Colorless/pale rose to yellow/reddish yellow-brown.|
Optics: a = 1.637-1.652; β= 1.645-1.658; γ= 1.649-1.663.
Biaxial ( – ), 2V= 75°.
Occurrence: In phosphate masses in granite pegmatites. Branchville, Connecticut: North Groton, New Hampshire; South Dakota.
Haute Vienne, France; Portugal; Germany: Poland, Pala, California: orange masses.
Comments: The colors are rich and lively, but the mineral is too soft for wear. Hureaulite is a collector gem and is very rare even in cabochon form.
Name: After the locality, Hureaux, France.