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Vermiculite is a hydrous phyllosilicate mineral which undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently; commercial furnaces can routinely produce this effect. Vermiculite forms by the weathering or hydrothermal alteration of biotite or phlogopite. [3]
Magyar; Norsk nynorsk; ... Vermiculite; Z. Zinnwaldite This page was last edited on 12 January 2020, at 03:53 (UTC). Text is available under the Creative ...
Vermiculite Like perlite, vermiculite is a mineral that has been superheated until it has expanded into light pebbles. If too much water and not enough air surrounds the plants roots, it is possible to gradually lower the medium's water-retention capability by mixing in increasing quantities of perlite.
Chrysocolla (/ ˌ k r ɪ s ə ˈ k ɒ l ə / KRIS-ə-KOL-ə) is a hydrous copper phyllosilicate mineral and mineraloid with the formula Cu 2 – x Al x (H 2 Si 2 O 5)(OH) 4 ⋅nH 2 O (x < 1) [1] or (Cu, Al)
Some vermiculite deposits, most notably those in Libby, Montana, are contaminated with chrysotile (as well as other forms of asbestos) that formed from diopside. [8] At relatively high temperatures, there is a miscibility gap between diopside and pigeonite, and at lower temperatures, between diopside and orthopyroxene.
Perlite boulders with fireweed in foreground. Perlite softens when it reaches temperatures of 850–900 °C (1,560–1,650 °F). Water trapped in the structure of the material vaporises and escapes, and this causes the expansion of the material to 7–16 times its original volume.
Calcium silicate competes in these realms against rockwool and proprietary insulation solids, such as perlite mixture and vermiculite bonded with sodium silicate. Although it is popularly considered an asbestos substitute, early uses of calcium silicate for insulation still made use of asbestos fibers.
Other cations such as Mg 2+ and K + ions exhibit even a more contrasted effect: highly hydrated magnesium ions are "swellers" as in vermiculite (totally expanded interlayer) while poorly hydrated potassium ions are "collapsers" like in illite (totally collapsed interlayer).