astrophyllite


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astrophyllite

[‚as·trə′fī‚līt]
(mineralogy)
(K,Na)3(Fe,Mn)7Ti2Si8O24(O,OH)7 A mineral composed of a basic silicate of potassium or sodium, iron or manganese, and titanium.
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One rock may also have traces of astrophyllite. Some of the rocks contain graphic and myrmekitic intergrowths of quartz and feldspar.
Astrophyllite [(K,Na).sub.3]([Fe.sup.2+]Mn)[Ti.sub.2][Si.sub.8][O.sub.24][(O,OH).sub.7], optically determined by Beydoun and Bichan (1969) and plumbomicrolite Pb[(TaNb).sub.2][O.sub.6](OH) of our new analysis by EMPA (see Edax record Fig.
Natrolite in the cavities is overgrown by calcite, fluorite, barytocalcite, podlesnoite, astrophyllite and, in minor amounts, burbankite, lemmleinite-K and fluorapophyllite.
There were a lot of fine minerals represented, from astrophyllite to zircon, all self-collected and all in fine condition.
Associated minerals are: natrolite, aegirine, microcline, catapleiite, fluorapatite, titanite, fluorite, galena, sphalerite, strontianite, annite, astrophyllite, lorenzenite, labuntsovite-Mn, kuzmenkoite-Mn, cerite-(Ce), edingtonite, ilmenite and calcite.
The principal rock of the Warsak igneous complex is a medium-grained, gneissic alkaline granite (Kempe, 1973) composed of microcline with minor albite, quartz, aegirine, riebeckite and astrophyllite. The gneissic lineation is imparted by the alignment of riebeckite and aegirine needles and is considered by Ahmad et al.
Occurrence: At Rasvumchorr, in veinlets cross-cutting natrolite of ristscorrite pegmatite; associated minerals are: microcline, aegirine, annite, astrophyllite, magnetite, fluorapatite, pyrophanite, thomsonite-Ca, etc.
Associated minerals at Nanna are aegirine, astrophyllite, analcime, calcio-ancylite-(Ce), catapleiite, fluorite, galena, gibbsite, leucophanite, microcline, natrolite, nafertisite, orthoclase, polylithionite, sodalite (var.
There were aegirine crystals with oddly clubbed ends; pale pink, blocky ancylite crystals; spiky balls of calcite; very complicated, water-clear crystals of an unknown mineral; tiny, resinous brown crystals of a second mineral showing a hexagonal pyramid termination, and pale brown sprays that were obviously astrophyllite.
Type-III: very fine-grained acicular crystals in sheaf-like aggregates (originally described as "witch's broom astrophyllite").
The syenite pegmatites contain calcium catapleiite, titanium-rich lavenite, lorenzenite, cesium-rich astrophyllite, kupletskite, pyrophanite, leucophanite, strontium-apatite, loparite, calcium-rich seidozerite, strontium-rich and zirconium-rich perrierite, brookite, landauite, murataite, polylithionite, brewsterite, chabazite, monazite, ancylite, bertrandite, vlasovite, hambergite.