Diaspore


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diaspore

[′dī·ə‚spȯr]
(mineralogy)
AlO(OH) A mineral composed of some bauxites occurring in white, lamellar masses; crystallizes in the orthorhombic system.

Diaspore

 

a mineral, natural aluminum hydroxide, AIOOH; contains 85 percent AI2O3 and 15 percent H2O, often with impurities of iron, chromium, manganese, and gallium oxides. Diaspores crystallizes in a rhombic system, forming lamellar, sometimes acicular, crystals. Its color is white, yellowish or pinkish white, or greenish gray. Its hardness on the mineralogical scale is 6–7; its density varies depending on the content of impurities, from 3,300 to 3,500 kg/m3. When annealed it becomes α-Al2O2 (corundum).

Diaspore is mainly concentrated in bauxites, where it appears as an ore-forming mineral together with boehmite and gibbsite. In association with corundum and chloritoids, it is found in emery deposits that are produced by the metamorphic change of bauxites. Diaspore is found in metamorphic, hydrothermic; and metasomatic deposits of the secondary quartz type.

References in periodicals archive ?
In this study, we evaluated the relation between the macrophyte diaspore bank in the sediment and the plant cover of aquatic macrophytes in a temporary floodplain lake that remains mostly unconnected with the river Parana.
The diaspores used in this bioassay were pre-germinated in distilled water (2 to 4 mm of radicle) and then distributed in plastic boxes (14 x 10 cm) lined with two filter papers moistened with 13 mL aqueous leaf extract, herbicide at 5 and 10% (positive control) or distilled water (negative control).
According to zeta potential measurement, minerals diaspore, kaolinite, illite and pyrophyllite, operating PZC diaspore, kaolinite, illite and pyrophyllite, were respectively about 6.68, 3.65, 2.88 and 2.51 [4]It was suggested to conduct the separation by using diaspore floatation method of kaolinite, illite and pyrophyllite, with a cationic collectors with a pH between 2 and 7.
Nelson, "Diaspore weight, dispersal, growth form and perenniality of central Australian plants," Journal of Ecology, vol.
coriaceum diaspore removal and dispersal distance, three Cerrado areas were selected (7[degrees]20'26.7" S - 39[degrees]28'12.9" W; 7[degrees]24'32.3" S - 39[degrees]22'37.4" W; 7[degrees]20'26.6" S - 39[degrees]28'46.7" W) with similar biotic and abiotic characteristics, and they were within approximately 10 to 50 km of one another.
Germination differences between the polymorphic diaspores. Journal of Arid Environments, vol.
Diaspore structure and germination ecophysiology of the babassu palm (Attalea vitrivir).
We aimed to analyze the sexuality, floral biology, and diaspore dispersal of Dorstenia arifolia and D.
Hydrochory is the dispersal by water, in which the diaspore floats on or is carried by water.
Xu, "Role of crystal structure in flotation separation of diaspore from kaolinite, pyrophyllite and illite," Minerals Engineering, vol.
Indigenous diaspore is a high density hard mineral.