The Red Ball mine, Calhoun County, Alabama, was once a source of iron for Confederate cannon, and now is a source of colorful strengite
, cacoxenite, beraunite, and kidwellite in earthy brown "bog iron" matrixes.
Beau Gordon (Jendon Minerals) found some excellent phosphate microcrystals at the Red Ball mine, Calhoun County, including golden yellow cacoxenite, gray-green botryoidal kidwellite, pink strengite
and colorless, transparent wavellite.
Chemical microanalysis reveals that pure strengite
is rare, end that most specimens have a significant component of aluminum.
forms a vitreous coating on green frondelite, and also white blebby crystals in vugs in the frondelite.
The Leveaniemi deposit in northern Sweden, renowned for violet strengite
, has produced some other rare phosphates during the last few years.
The mine has produced an interesting suite of minerals in recent years, including pale blue to green aquamarine, alpine-like smoky quartz crystals, spessartine, danburite, columbite, cassiterite, helvite, and numerous phosphates including apatite, lithiophilite, purpurite, herderite, strengite
, phosphosiderite, hureaulite, robertsite, eosphorite, frondelite and mitridatite (A.
Thin fracture coatings and vug linings of botryoidal, dark green to black dufrenite have been observed very rarely, associated with radial sprays of strengite
, minute cubic crystals of pharmacosiderite, and local sprays of meurigite.
In acid soils, P solubility is mostly controlled by the minerals strengite
([FeSO.sub.4].2[H.sub.2]O) and variscite ([AlPO.sub.4].2[H.sub.2]O).
It occurs in partly oxidized gray orthoclase-quartzpyrite rock, following earlier strengite
and followed by an unidentified green member of the rockbridgeite family (Eckel, 1997).
sub.2] Siderite Fe#C[O.sub.3] Oxides Sulfides Cassiterite Sn[O.sub.2] Bornite (Cu sulfide) [Cu#.sub.5] Fe#[S#.sub.4] Hematite [Fe#.sub.2][O.sub.3] Chalcocite [Cu#.sub.2]S# Limonite (bog iron) Fe#O(OH) Chalcopyrite CuFe#[S#.sub.2] x [H.sub.2]O (Fe sulfide) Fe#[S#.sub.2] Magnetite [Fe#.sub.3][O.sub.4] Galena PbS# Shalerite ZnS# Phosphatic Minerals Trace Elements Apatite [Ca#.sub.5](F#,Cl#) Carnotite [K#.sub.2](U[O.sub.2]) [(P#[O.sub.4]).sub.3] [(V#[O.sub.4]).sub.2] Strengite
FeP#[O.sub.4] x Fluorite Ca#[F#.sub.2] 2 [H.sub.2]O Variscite AlP#[O.sub.4] x Halite (Rock Salt) NaCl# 2 [H.sub.2]O Note: Essential macro- and micronutrients are indicated with #.
Williams BG, Patrick WH Jr (1971) The effect of [E.sub.h] and pH on the dissolution of strengite
. Nature Physical Science 234, 16-17.
From the Boa Vista mine (a phosphate pegmatite) in Galileia, Minas Gerais comes variscite as bright red druses of microcrystals colorfully resting on a matrix of purple strengite
and other rare phosphates.