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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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.
Many fine crystals of pezzottaite were recovered from a single pocket containing mostly smoky quartz, amazonite and cleavelandite. In addition, multicolored tourmaline, pink-yellow-green spodumene, lithian muscovite and danburite occurred in this pocket which reportedly measured at least 1.2 X 3 X 3 m.
Pezzottaite occurs in three distinct habits: (1) irregularly shaped flat masses (up to 8 cm in diameter) that fill cavities between cleavelandite, quartz and tourmaline; (2) subhedral-to-euhedral hexagonal tabular crystals up to 10 cm across; (3) small (a few mm) flat to equant to elongated crystals attached to faces of large tourmaline crystals.
A number of sizable specimens were recovered associated with quartz and cleavelandite, and a few with well-formed, pale crystals of morganite.
cleavelandite), microcline, and lepidolite are common in pockets, while spodumene has not been reported from the Tourmaline Queen.
The best specimen known to have come from the King mine is "The Steamboat," a 27 x 32-cm specimen consisting of two parallel, bicolored elbaite crystals on quartz and cleavelandite. This specimen was originally in the Roebling collection and is now in the National Museum of Natural History (Smithsonian Institution) (see Bancroft, 1973).
Much cleavelandite feldspar was still present along with subhedral to euhedral quartz crystals.
Associations include cookeite and cleavelandite. The crystals, which have the same habit as zircon, are euhedral to irregular and occur in sizes up to 1 cm.
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.