The Kempton brothers beryl pegmatite, south of Pyramid Hill, is the type locality for clinobisvanite, where it was found with beryl, ferrocolumbite, triphylite, rockbridgeite
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).
Strengite is associated with cacoxenite and a member of the rockbridgeite family (Eckel, 1997).
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.
More recently the list has been expanded to include jahnsite (Moore and Ito, 1978a), arrojadite (Moore and Ito, 1979), dufrenite and one unidentified zinc phosphate (Hirson, 1965) having lower refractive indices than the zincian rockbridgeite of Lindberg and Frondel, 1950), a kidwellite-like mineral (Moore and Ito, 1978b) and johnsomervilleite (Araki and Moore, 1981).
Vein deposition of montebrasite, pyrite, quartz, sphalerite, tourmaline and zircon coexists with replacements of triphylite (usually along cleavages) by heterosite, barbosalite, frondelite, jahnsite, phosphosiderite, rockbridgeite, tavorite and manganese oxides.
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.
The silicate assemblage consists of altered albite as a host for apatite, hureaulite, goethite, gordonite, leucophosphite, phosphosiderite, rockbridgeite, saleeite, tourmaline and variscite; altered beryl as host for faheyite, moraesite, roscherite and variscite, and muscovite hosting replacements and vug fillings of apatite, bermanite, childrenite, faheyite, frondelite, montebrasite, roscherite and variscite.
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).
Associated minerals in the cavities are: wardite, eosphorite, cyrilovite, a kidwellite-like mineral, rockbridgeite
, leucophosphite, saleeite and montmorillonite.
The latter are available from the Rorksmiths and are associated with rich barbosalite, rockbridgeite
, vivianite and other minerals.
Then, within the extensive Indian Mountain complex of altered pegmatites in Cherokee County, a new dig called the Fault Line Prospect has yielded sparkly pale green seam linings of microcrystals of kidwellite, lavender strengite in radial balls to 4 mm, and some beautiful deep green sprays of acicular rockbridgeite
to 6 mm.