cleavelandite


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cleavelandite

[′klēv·lən‚dīt]
(mineralogy)
A white, lamellar variety of albite that is almost pure NaAlSi3O8 and has a tabular habit, with individuals often showing mosaic developments and tending to occur in fan-shaped aggregates.
References in periodicals archive ?
Most specimens show the apatite-(CaOH) crystals resting on microcline crystals or cleavelandite plates, and in a smaller number of specimens the crystals are perched on quartz, muscovite or albite.
Pseudo-hexagonal crystals up to 10 cm have been found perched on groups of cleavelandite crystals, and forming loose clusters.
In many pockets the large quartz crystals are found perched on clusters of cleavelandite crystals and on mixtures of albite, muscovite and microcline.
They found a pocket containing numerous morganite specimens, most on a matrix of cleavelandite and quartz, along with a modest amount of kunzite.
Most crystals are highly lustrous and up to 8 cm in size; many are on a cleavelandite matrix (Foord et al.
This specimen consists of a large plate of cleavelandite, approximately 50 cm across, with seven large (up to 15 cm) morganite crystals, plus numerous smaller ones scattered about one side of the plate.
1991), minerals found in pockets in the pegmatite include quartz, perthitic microcline, cleavelandite, muscovite, tourmaline (schorl), beryl, columbite, and apatite.
Several large matrix specimens were recovered from this pocket, including a 25-cm plate of cleavelandite and smoky quartz with two large, dark green elbaite crystals and two blue topaz crystals, now in the Carnegie Museum of Natural History, Pittsburgh, Pennsylvania.
Stibiotantalite, as I said, was not an uncommon mineral at Muiane, and usually showed up in association with rubellite tourmaline and clusters of cleavelandite albite.
We've known this occurrence in the form of loose, single thumbnail-sized spheres of tiny pinkish-grayish brown stokesite crystals, but the new specimens are much larger; indeed some are on matrix, up to 10 x 12 cm, of greenish cleavelandite with multiple stokesite spheres sitting in solution cavities.