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Formula: Fe3+Al7(PO4)4(PO3OH)2(OH)8(H2O)8.8H2O
Hydrated phosphate
Crystal system: Monoclinic
Specific gravity: 2.27 measured, 2.294 calculated
Hardness: 1½
Streak: White
Colour: Colourless, white, greyish white
Solubility: Soluble with difficulty in hydrochloric acid, easily soluble in hot sulphuric acid
Environments
Pegmatites
Hydrothermal environments
Matulaite occurs as an uncommon secondary mineral in the
oxidised zone of phosphatic iron deposits. Associated minerals include
beraunite, rockbridgeite,
dufrénite, cacoxenite,
strengite, wavellite,
goethite, hematite and
afmite
(HOM).
Localities
At the LCA Mine, Gaston County, North Carolina, USA, matulaite occurs in the
pegmatite
(AM 65.1067).
At the type locality, the Bachman Mine, Hellertown, Lower Saucon Township, Northampton County, Pennsylvania, USA,
matulaite occurs in small rosettes of thin tabular crystals and botryoidal forms and one perfect cleavage.
It occurs as incrustations on chert, the youngest mineral of the association
beraunite, rockbridgeite,
dufrénite, cacoxenite,
strengite and wavellite
(AM 65.1067).
Matulaite from the Bachman Mine - Image
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