The standards selected for Mn were birnessite [([(Na, Ca).sub.0.5]([Mn.sup.4+], [Mn.sup.3+]).sub.2] [O.sub.4].1.5[H.sub.2]O), hureaulite
([(Mn, Fe).sub.5][H.sub.2][(P[O.sub.4]).sub.4].4[H.sub.2]O), manganocalcite (Mn-CaC[O.sub.3]), Mn-carbonate (MnC[O.sub.3]), Mn-sulfate (MnS[O.sub.4]), bixbyite ([Mn.sub.2][O.sub.3]), pyrolusite (Mn[O.sub.2]), and switzerite ([(Mn, Fe).sub.3][(P[O.sub.4]).sub.2].7[H.sub.2]O).
Strunz (1970) found hureaulite
[[Mn.sub.5][H.sub.2][(P[O.sub.4]).sub.4] x 4[H.sub.2]O] and reddingite [[Mn.sub.3][(P[O.sub.4]).sub.2] x 2[H.sub.2]O] as naturally occurring minerals in soil.
Kay was a founding member of the Southern California Micromineralogists Society, and after the German trip she was able to bring, for example, exotic Hagendorf-Sud microspecimens of strunzite, strengite, hureaulite
, phosphophyllite etc.
Jordi was also proud of his new specimens from the Cigana (formerly the Jocao) mine near Galileia, Minas Gerais: brown matrix pieces to 10 cm showing lustrous reddish brown crystals of reddingite to 5 mm and of hureaulite
to 1 cm.
Secondary phosphates found in the Stewart pegmatite include hureaulite
, sicklerite, purpurite, heterosite, stewartite, and phosphosiderite.
Minerals in the pegmatite are: quartz, microcline, muscovite, albite, amblygonite, "apatite," beryl, uraninite, elbaite, members of the tantalite group, secondary uranium minerals, triphylite, triplite, purpurite, rockbridgeite, tavorite, barbosalite, hureaulite
, eosphorite, phosphosiderite, carlhintzeite, colquirite, pachnolite, ralstonite and fluellite.
Correia Neves and Lopes Nunes (1968) described bermanite, eosphorite, variscite, phosphosiderite, hureaulite
, montebrasite, fluorapatite, amblygonite, and triplite from Alto Ligonha pegmatites.
The unaltered triphylite cores are separated from a massive heterosite-ferrisicklerite zone by a porous, altered triphylite zone with sponge-like cavities containing terminated crystals of hureaulite
, crystalline aggregates of blue vivianite, bladed blackish green barbosalite, and yellow earthy tavorite.
In the immediate area surrounding the Berilo Branco pegmatite are several other noteworthy occurrences including the Frente Boca de Fogo mine (fine beryl), the Boca Rica mine (good rockbridgeite and hureaulite
crystals) and the Fazenda Campo Alegre (where 3 tons of large heliodor crystals up to 80 kg each were found).
Although I generally don't like "reporting" on things I have not actually seen, I feel it my duty to pass on the well-attested fact that two specimens of hureaulite
recently unearthed at Shengus, Pakistan are among the world's best examples of the species: a significant claim, considering how good the ones from Brazil can get.
Excellent specimens of bright pink hureaulite
crystals have been found at both Conselheira Pena, and at the Criminoso mine, north of Sao Jose da Safira, Minas Gerais.
Scattered much more widely about the show were the translucent violet-pink hureaulife crystals (with reddingite and other phosphates) in glistening pegmatite-cavity fillings, some with well-defined hureaulite
individuals to 5 mm: at least a dozen dealers, including of course most of the Brazilians, had these.