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 ?
Most myrmechorous diaspores have a lipid-rich structure, such as an elaiosome, which is the food item desired by the ant; the attached seed is just ballast.
Germination was evaluated in a bifactorial arrangement (3x2) consisting of three temperatures (20, 25 and 30[degrees]C) and two light conditions (12 hours photoperiod and continuous darkness) for the diaspores newly harvested and a bifactorial arrangement (4x2), corresponding to four temperatures (15, 20, 25 and 30[degrees]C) and two light conditions (12 hours photoperiod and continuous darkness) for diaspores analyzed after storage.
From the tested models, only Modified Henderson showed higher coefficient of determination and lower values of relative mean error and estimated mean error, besides lower magnitude of Chi-square values; thus, it was selected for the prediction of the hygroscopic equilibrium of pequi diaspores.
SEM+EDS analyses show that most of the diaspores are cryptocrystalline with a small particle size and mainly coexists with ferrohydrite.
In the late 1980s, outstanding single and V-twinned crystals of gemmy pale brown diaspore began to reach the international market; various localities have appeared on labels, but generally the specimens come from an emery-mining region between the towns of Aydin and Mugla in southwestern Turkey, inland from the ruins of ancient Ionian Greek cities (e.
The Petri dishes that contained the diaspores were taken to a germination chamber (Mangelsdorf type to lettuce and B.
The shepherds and their live-stock transport energy, nutrients and diaspores with dung, fur and hoofs from various habitats in the outfields via a finely veined network of routes to the infields and settlements.
Interactions between ants and the diaspores of some common spring-flowering herbs in West Virginia.
Dans cet article, l'auteure examine deux recits diaspores de l'Asie-pacifique traitant d'enfants d'immigrants : Among the White Moon Faces: An Asian-American Memoir of Homeland, de Shirley Geok-lin Lim et Volcano: A Memoir of Hawai'i, de Garrett Hongo.
Seed mass and dispersal capacity in wind-dispersed diaspores.