vermiculite

vermiculite
/veuhr mik"yeuh luyt'/, n.
any of a group of platy minerals, hydrous silicates of aluminum, magnesium, and iron, that expand markedly on being heated: used in the expanded state for heat insulation and as a plant growth medium.
[1815-25, Amer.; VERMICUL(AR) + -ITE1]

* * *

      clay mineral similar to montmorillonite in structure and, in some cases, composition. Vermiculite is typically formed by the alteration of biotite, and it occurs both as large pseudomorphs replacing biotite and as small particles in soils and ancient sediments. It is also formed at the interface between acidic intrusive rocks and basic rocks such as pyroxenites and dunites. Large deposits occur in South Africa, Australia, Russia, and Brazil. In the United States, it is found in Montana and the Carolinas. For chemical formula and detailed physical properties, see clay mineral (table).

      When rapidly heated to about 300° C (570° F), vermiculite can expand to 20 times its original thickness; its name, from the Latin word meaning “to breed worms,” alludes to this property. In its natural state the mineral has little commercial use, but exfoliated vermiculite is extremely light (specific gravity as low as 0.09) and is used in lightweight concrete or plaster, for thermal and acoustic insulation, or as a packing medium, a soil conditioner, a starting medium for seeds, and a filler or extender in paper, paint, or plastics.

* * *


Universalium. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Vermiculite — Catégorie IX : silicates[1] Général …   Wikipédia en Français

  • vermiculite — [ vɛrmikylit ] n. f. • 1875; de vermiculé et lite, pour lithe ♦ Minér., Techn. Silicate hydraté provenant de l altération du mica, se présentant en petites écailles. La vermiculite est utilisée comme isolant et adsorbant. ● vermiculite nom… …   Encyclopédie Universelle

  • Vermiculite — Ver*mic u*lite, n. [L. vermiculus, dim. of vermis worm.] (Min.) A group of minerals having, a micaceous structure. They are hydrous silicates, derived generally from the alteration of some kind of mica. So called because the scales, when heated,… …   The Collaborative International Dictionary of English

  • vermiculite — 1814, from L. vermiculari (from vermiculus, dim. of vermis; see WORM (Cf. worm)) + ITE (Cf. ite) …   Etymology dictionary

  • vermiculite — ☆ vermiculite [vər mik′yə līt΄ ] n. [< L vermiculus, dim. of vermis,WORM + ITE1] any of a number of very soft, monoclinic, hydrous silicate minerals resulting usually from alterations of mica and occurring in tiny, leafy scales that expand… …   English World dictionary

  • Vermiculite — Infobox mineral name = Vermiculite category = boxwidth = boxbgcolor = caption = formula = (MgFe,Al)3(Al,Si)4O10(OH)2·4H2O color = Bronze Yellow habit = Clay, scaly, aggregate system = Monoclinic twinning = cleavage = Perfect fracture = Uneven… …   Wikipedia

  • Vermiculite — Vermiculit Vermiculit Chemische Formel (Mg0,5,Ca0,5,Na,K)0,7(Mg,Fe,Al)3[(OH)2|(Al,Si)2Si2O10] · 4H2O Mineralklasse Drei Schichtsilikate (Phyllosilikate) VIII/H.21 10 (nach …   Deutsch Wikipedia

  • vermiculite —    A product commonly used by gardeners, who mix it into soil in order to aerate the soil. Vermiculite is sometimes mixed into plaster as an aggregate to make plaster easier to carve, and to give it a pleasing texture. An alternative softening… …   Glossary of Art Terms

  • vermiculite — vermikulitas statusas T sritis chemija apibrėžtis Mineralas. formulė Formulę žr. priede. priedas( ai) Grafinis formatas atitikmenys: angl. vermiculite rus. вермикулит …   Chemijos terminų aiškinamasis žodynas

  • vermiculite — noun Etymology: Latin vermiculus little worm Date: 1824 any of various micaceous minerals that are hydrous silicates resulting usually from expansion of the granules of mica at high temperatures to give a lightweight highly water absorbent… …   New Collegiate Dictionary

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”