General Information:
Chemical Formula:CaFe+++4(PO4,SO4)2(OH)8·4-6(H2O) (?)
Composition:(Molecular Weight = 320.74 gm)Iron 34.82 %
FePhosphorus 9.66 %
P Hydrogen 3.14 %
H Oxygen 52.38 %
O Empirical Formula: Fe3+2(PO4)(OH)3·3.5(H2O)
Locality:Berneau, near Visâ, LiÅ ge, Belgium.
Name Origin:Named after J.S.P.J. Delvaux de Feuffe (1782-1863), Belgian chemist who first described and analyzed the mineral.
Physical Properties: Cleavage:None
Color:yellowish brown, brown, reddish brown, or brownish black.
Density:1.8 - 2, Average = 1.9
Habits:Amorphous - No crystalline form or imitative shape., Concretionary - Rounded massive fine-grained materials., Stalactitic - Shaped like pendant columns as stalactites or stalagmites ( e.g. calcite).
Hardness:2.5 - Finger Nail
Luster:Vitreous - Greasy
Streak:yellow
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