Halloysite


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Related to Halloysite: Nontronite, beidellite

halloysite

[hə′lȯi‚sīt]
(mineralogy)
Al2Si2O5(OH)4·2H2O Porcelainlike clay mineral whose composition is like that of kaolinite but contains more water and is structurally distinct; varieties are known as metahalloysites.

Halloysite

 

(named for the Belgian geologist J. B. Omalius d’Halloy, 1783-1875), a claylike mineral of the group of layered silicates having the chemical composition Al4[Si4O10](OH)8·4H2O. It is close in composition to kaolinite, from which it is distinguished by a higher water content. Halloysite crystallizes in a monoclinic system. It is found in the form of claylike crypto-crystalline aggregates. The coloration is usually white but can sometimes be from yellowish to brown (from iron oxides), with a dull luster. Its hardness on the mineralogical scale is one to two; its density is 2,000 to 2,200 kg/m3. Halloysite is a typical product of the weathering of the aluminum silicates of igneous rocks, especially feldspars. It is common, but large accumulations are unusual.

References in periodicals archive ?
Previous studies have shown that the halloysite nanotubes can be dispersed in starch-based polymer matrix by melt-extrusion [15-17].
Halloysite, a 1:1 clay mineral chemically similar to kaolinite except in its higher hydrated water content shows tubular morphology but also spherical, platy and semi rolled forms.
Preliminary development work shows that the existence of halloysite as well as other clay minerals found in areas of the Dragon Mine resource produce ceramic proppants having appealing crush strength, permeability and specific gravity features that meet or surpass certain performance metrics of several rivaling ceramic-based products.
Applied Minerals is a leading producer of halloysite clay from its wholly-owned Dragon Mine property inUtah.
HNTs are naturally occurring, nontoxic and have a hollow tube structure unique to halloysite clay.
A key advantage over traditional nanoclays is that halloysite nanotubes do not need exfoliation, which involves separating thin layers of nanoclay (like peeling an onion) with chemicals and other processing steps.
Key benefits of the halloysite nanotubes for plastics include an increase in nanocomposite material strength and modulus with no sacrifice in ductility, improved uniformity of finished materials, reduced component weight, and improved performance at higher temperatures, says NaturalNano.
One theory of why halloysite forms into tubes is due to shearing but another belief is that it is caused by interaction with water, which causes halloysite sheets to roll into tubes.
Additional keywords: 2:1-2:1:1 intergrade minerals, clay content, halloysite, kaolinite, weathering process.
the "Company") is a leading global producer of Halloysite Clay from its wholly-owned Dragon Mine property in Utah.
4 million short tons is based upon a cut-off grade of 20% clay and represents the largest deposits of high quality feldspar, quartz, kaolin and halloysite in the Western United States.
CRADA Aimed at Developing a Remediation Solution for Oil Contaminated Marshlands Using Dragonite[TM] Halloysite Clay Technology