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 ?
It is dependent on activation by water, although it is not hydrochory, as water is not transporting the diaspore.
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.
Thermal gravimetric analysis (TGA) of diaspore samples was preformed on Metter-Toledo TGA analyzer TGA/SDTA851e/LF using an air flow rate of 50 mL/min.
The diaspores of target species were sown in 9 cm Petri dishes, with two filter papers moistened with 5 mL aqueous leaf extract, oxyfluorfen herbicide (positive control) or distilled water (negative control).
Aluminum hydroxide minerals in various proportions except bauxite are conventionally found in Gibbsite with the combination of [Al (OH) 3] and polymorphs like boehmite and diaspore [AlO (OH)].
Boehmite and diaspore require higher operating conditions.
Caryocar coriaceum (Caryocaraceae) diaspore removal and dispersal distance on the margin and in the interior of a Cerrado area in Northeastern Brazil
Effects of experimental restoration on the diaspore bank of an upland moor degraded by Pteridium aquilinum invasion.
A schizocarpic fruit, of samaroid subtype, being a dry winged tricarpellate fruit, represents the diaspore (Figure 1A-C).