Along with gem spodumene and tourmaline, Jahns and Wright (1951) list quartz, perthitic microdine, albite, beryl (morganite and aquamarine), bavenite, bertrandite, numerous bismuth-containing minerals including native bismuth, bismuthialte, bismutite, and bismite, and nurnerous phosphates including lithiophilite, triphylite
, sickletite, purpurite, heterosite, stewartite, and hureaulite.
Large phosphate pebbles and boulders are often exposed in the creek bed after heavy rains; these are generally massive triphylite or frondelite, with or without alteration minerals, or heterosite sometimes showing good crystals.
They reported (Pecora et al., 1950) that the central zone contained "irregular bodies of triphylite, which were altered partly by hydrothermal solutions during consolidation of the pegmatite, and partly by surficial waters during weathering.
Summing up their work on Sapucaia phosphates, Lindberg and Pecora (1958) listed their apatite, bermanite, childrenite, gordonite, heterosite, hureaulite, leucophosphite, lipscombite, metastrengite (= phosphosiderite), montebrasite, roscherite, saleeite, strengite, triphylite, variscite and vivianite as having been positively identified, in addition to the new species.
After a period of abandonment during the 1960's and early 70's, some small pits were excavated in 1975-1977 into the northeastern side of the core; a beryl-rich zone with coralloid blue vivianite-stained triphylite in feldspar was discovered.
The triphylite assemblage occurs as fracture fillings and replacements in massive triphylite.
The frondelite assemblage consists of residual heterosite, [TABULAR DATA FOR TABLE 1 OMITTED] montebrasite and triphylite enclosed by frondelite; massive replacement of frondelite by cyrilovite, cryptomelane and leucophosphite; and fracture coatings in frondelite of bermanite, cyrilovite, goethite, leucophosphite, lipscombite, mitridatite, moraesite, opal, phosphosiderite, rockbridgeite, variscite and manganese oxides.
Triphylite, with Fe:Fe + Mn + Mg [greater than] 1.0, has also been observed, but is uncommon.
Central Pegmatite Sulfide Pods Phosphate Pods Primary Minerals Primary Minerals Primary Minerals Albite Bismuthinite (?) Albite Beryl Covellite Gahnite Fluorapatite Digenite Lithiophilite Gahnite Galena Spessartine Manganocolumbite Hessite Triplite Microcline Triploidite Muscovite Secondary Triphylite Pyrochlore Minerals UK-1 Quartz Chrysocolla Zircon Rutile (niobian) Malachite Schorl UK-2 Secondary Phosphates Spessartine Crandallite Spodumene Eosphorite Uranmicrolite Fluorapatite Uranpyrochlore Zircon Secondary Minerals Coronadite Hectorite ACKNOWLEDGMENTS
The former are associated with a well-crystallized, gray reddingite-like mineral, triphylite, vivianite and frondelite, and are available from both Luis Menezes and Carlos Barbosa (Rue Cell Roberto Soares Ferreira 586, Bairro Vila Bretas, 35030 Governador Valaderes, Minas Gerais, Brazil).
Carlos also reports that Linopolis is producing many brazilianite crystals (to 5 cm) as well as eosphorite and triphylite gemmy enough to be cut into flawless 0.5 ct gems.
This occurs as white-to-pale tan, powdery coatings on stained triphylite, giving one the feeling that much more isokite than we realize is probably in the world masquerading as earthy "apatite."