Vermiculite
General
Category	Mineral
Chemical formula	(MgFe,Al)3(Al,Si)4O10(OH)2.4H2O
Identification
Color	Honey
Crystal habit	Clay, scaly, aggregate
Crystal system	Monoclinic
Cleavage	Perfect
Fracture	Uneven
Mohs Scale hardness	2-3
Luster	Vitreous
Refractive index	Translucent
Pleochroism	None
Streak	Pale yellow
Specific gravity	2.4-2.7

Vermiculite is a natural, non toxic mineral that expands with the application of heat. The expansion process is called exfoliation and it is routinely accomplished in purpose-designed commercial furnaces. Vermiculite is formed by hydration of certain basaltic minerals. The former W.R. Grace mine in Libby, Montana was the largest and oldest vermiculite mine in the United States, but other deposits exist in South Carolina and Virgina, and large commercial vermiculite mines currently exist in South Africa, China, Brazil, and a several other countries. Vermiculite Source: US Government File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Minerals are natural compounds formed through geological processes. ... This article or section does not cite any references or sources. ... In mineralogy, shape and size give rise to descriptive terms applied to the typical appearance, or habit of crystals. ... A crystal system is a category of space groups, which characterize symmetry of structures in three dimensions with translational symmetry in three directions, having a discrete class of point groups. ... In crystallography, the monoclinic crystal system is one of the 7 lattice point groups. ... Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types: Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes. ... For fractures in geologic formations, see Rock fracture. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ... Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock or mineral. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... Pleochroism is an optical phenomenon where due to double refraction of light by a colored gem or crystal, the light is divided into two paths which are polarized at a 90° angle to each other. ... The streak (also called powder color) of a mineral is the color of the powder produced when it is dragged across a unweathered surface. ... Relative density (also known as specific gravity) is a measure of the density of a material. ... Minerals are natural compounds formed through geological processes. ... In physics, heat, symbolized by Q, is defined as a form of energy whose absorption raises the temperature of a body, not existing in the transition state, and abstraction of which from the same body lowers its temperature. ... Exfoliation has several meanings: Dead skin cells? No: geological exfoliation of granite at Enchanted Rock State Natural Area, Texas, USA Exfoliation (cosmetology), is a cosmetic technique aimed at removing dead skin cells from the face and body. ... In chemistry, hydration is the condition of being combined with water. ... In geology, mafic minerals and rocks are silicate minerals, magmas, and volcanic and intrusive igneous rocks that have relatively high concentrations of the heavier elements. ...

Structure

Vermiculite is a 2:1 clay, meaning it has 2 tetrahedral sheets for every one octahedral sheet. It has a medium shrink-swell capacity and is considered a limited-expansion clay. Vermiculite has a high cation exchange capacity at 100-150 meq/100g. Vermiculite clays are weathered micas in which the K⁺ ions between the molecular sheets are replaced by Mg²⁺ and Fe²⁺ cations. The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ... A tetrahedron (plural: tetrahedra) is a polyhedron composed of four triangular faces, three of which meet at each vertex. ... An octahedron (plural: octahedra) is a polyhedron with eight faces. ... This article does not cite its references or sources. ... In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ...

Commercial uses

• moulded shapes, bonded with sodium silicate for use in:
  • high-temperature insulation
  • refractory insulation
  • fireproofing of structural steel and pipes
• soil conditioner
• as loose-fill insulating
• packing material
• suitable as a substrate for various animals and/or incubation of eggs
• lightweight aggregate for plaster, proprietary concrete compounds, firestop mortar and cementitious spray fireproofing
• component of the interior fill for firestop pillows, along with graphite
• carrier for dry handling and slow release of agricultural chemicals
• soil additive for plants, together with perlite for potted plants
• growing medium for hydroponics.
• means to permit slow cooling of hot pieces in glassblowing, lampwork, steelwork, and Glass beadmaking
• used in in-ground swimming pools to provide a smooth pool base
• used in commercial handwarmers

Sodium silicate, also known as water glass or liquid glass, available in aqueous solution and in solid form, is a compound used in cements, passive fire protection, refractories, textile and lumber processing. ... Fireproofing, a passive fire protection measure, subject to bounding, refers to the act of making materials or structures more resistant to fire, or to those materials themselves. ... The steel cable of a colliery winding tower. ... Pipe is a tube or hollow cylinder for the conveyance of fluid. ... Soil conditioners, also called soil amendments, are materials added to soil to improve plant growth and health. ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... In biology a substrate is the surface a plant or animal lives upon. ... The word incubation (from the Latin incubare, to lie upon) can mean the following: In chemistry or biochemistry, incubation refers to maintaining a system under specific conditions in order to promote a particular reaction. ... Gypsum based plaster used in spray fireproofing in a low-rise industrial building in Vancouver, British Columbia. ... Concrete being poured, raked and vibrated into place in residential construction in Toronto, Ontario, Canada. ... Firestop after fire exposure during fire test in Tulsa, Oklahoma. ... Fireproofing, a passive fire protection measure, subject to bounding, refers to the act of making materials or structures more resistant to fire, or to those materials themselves. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Graphite (named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): to draw/write, for its use in pencils) is one of the allotropes of carbon. ... Expanded Perlite Perlite is an amorphous volcanic glass that has a relatively high water content. ... NASA researcher checking hydroponic onions with Bibb lettuce to his left and radishes to the right Example of Autotrophic Metabolism Hydroponics or hydroculture is a method of growing plants using mineral nutrient solutions instead of soil. ... Sculpting hot blown glass. ... Lampworking is glassworking using a torch to melt and shape the glass. ... Lampwork glass beads. ...

Commercial manufacture of exfoliated vermiculite

Vermiculite output in 2005

In 2005, South Africa was the top producer of vermiculite with about 40% world share followed by the USA and China, reports the British Geological Survey. Image File history File links Size of this preview: 800 × 351 pixelsFull resolution (1425 × 625 pixel, file size: 58 KB, MIME type: image/png)This bubble map shows the global distribution of vermiculite output in 2005 as a percentage of the top producer (South Africa - 209,801 tonnes). ... Image File history File links Size of this preview: 800 × 351 pixelsFull resolution (1425 × 625 pixel, file size: 58 KB, MIME type: image/png)This bubble map shows the global distribution of vermiculite output in 2005 as a percentage of the top producer (South Africa - 209,801 tonnes). ... The British Geological Survey is a publicly-funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its continental shelf by means of systematic surveying, monitoring and research. ...

While some exfoliators focus on only a few of the possible applications, others can provide vermiculite products for all its applications. It is common for vermiculite exfoliators to also exfoliate perlite, as both are often sold together. To set up a new exfoliation process, it is possible to find expert consultants to advise in the design and construction of the desired facilities. Vermiculite exfoliators have an international trade association called The Vermiculite Association [1], to represent the industry's interests and to exchange information. Many of its members also maintain memberships in The Perlite Institute[2].

Fireproofing

For many years, since the advent of the asbestos removal business, before which nearly everyone sold asbestos-based spray fireproofing, vendors could be cleanly categorised into users of MMMF (man-made-mineral-fibres), which included both rockwool and ceramic fibres, and cementitious sprays, whereby the binder was typically portland cement and the lightweight aggregate inside the plaster was vermiculite. For many years, makers of the cementitious products would point out the ill health effects that are possible from overexposure and lack of proper industrial hygiene procedures when working with MMMF. Vendors of the MMMF products would point out the possibility of asbestos contamination, particularly with US mined vermiculite ore. Ironically, both sides were defending against lawsuits in the asbestos litigation and eventually stopped pointing out these particular weak spots about one another, which makes sense, since most affected manufacturers are still in receivership as a means of dealing with the results of the asbestos litigation. One large British manufacturer of asbestos products even had to discontinue selling anything to North America directly, having to rely on surrogate trading companies for sales to that continent now. Fibrous asbestos on muscovite Asbestos Asbestos Asbestos (a misapplication of Latin: asbestos quicklime from Greek : a, not and sbestos, extinguishable) describes any of a group of minerals that can be fibrous, many of which are metamorphic and are hydrous magnesium silicates. ... Mineral wool, also known as mineral cotton, silicate cotton, stone wool, slag wool, rockwool, and rock wool, is an inorganic substance used for insulation and filtering. ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... In the most general sense of the word, cement is a binder, a substance which sets and hardens independently, and can bind other materials together. ... Sampling fast set Portland cement Portland cement is the most common type of cement in general usage, as it is a basic ingredient of concrete, mortar and plaster. ... Aggregate is the component of a composite material used to resist compressive stress. ... Gypsum based plaster used in spray fireproofing in a low-rise industrial building in Vancouver, British Columbia. ... Hygiene refers to practices associated with ensuring good health and cleanliness. ... It has been suggested that civil trial be merged into this article or section. ... Manufacturing is the transformation of raw materials into finished goods for sale, or intermediate processes involving the production or finishing of semi-manufactures. ... Bankruptcy is a legally declared inability or impairment of ability of an individual or organization to pay their creditors. ... World map showing North America A satellite composite image of North America. ...

Controversy over health risks

An article published in the Salt Lake Tribune on December 3, 2006 reported that vermiculite and Zonolite had been found to contain asbestos which had led to cancers such as are found in asbestos related cases. The article stated that there had been a "cover-up" by W. R. Grace and others regarding the health risks associated with vermiculite and that several sites in the Salt Lake Valley had been remediated by the EPA when they were shown to be contaminated with asbestos. W. R. Grace has vigorously denied these charges. Marquis of the Salt Lake Tribune on the Tribune Building in Downtown Salt Lake City The Salt Lake Tribune is Salt Lake City, Utahs largest-circulated local daily newspaper. ... William Russell Grace (born May 10, 1832, Cobh (Ireland); died March 21, 1904, New York) was the first Roman Catholic mayor of New York City and the founder of W. R. Grace and Company. ...

Although vermiculite does not contain asbestos, and vermiculite mines throughout the world have been regularly tested and found to be free of asbestos, the former vermiculite mine in Libby, Montana did have asbestos---in fact, it was found to have developed with and to be co-mingled with significant amounts of asbestos. And unfortunately, the mine had been operating since the 1920's, and environmental and industrial controls were virtually non-existent until the mine was purchased by the W.R. Grace Company in 1963. Consequently many of the former miners and residents of Libby had been affected and continue to suffer health problems.

In the Libby deposit, vermiculite was extracted under the commercial name Zonolite (the Zonolite brand was acquired by the W.R. Grace Company in 1963[3]). Mining operations on the Libby site stopped in 1990 in response to asbestos contamination. The United States government estimates that vermiculite was used in more than 35 million homes, but currently does not recommend its removal. (Health problems with the Libby vermiculite seem to be confined to the workers at the mine and to residents of the town of Libby, and not to end-users of the exfoliated or expanded vermiculite. W. R. Grace and Company NYSE: GRA is a conglomerate founded in 1854 by William Russell Grace (1832-1904). ... Libby is a city in Lincoln County, Montana, United States. ... The government of the United States, established by the United States Constitution, is a federal republic of 50 states, a few territories and some protectorates. ...

See also

• Passive fire protection
• Fireproofing
• Firestop
• Asbestos
• Perlite
• Sodium silicate
• Plaster
• List of minerals
• Square foot gardening

Fire-resistance rated wall assembly with fire door, cable tray penetration and intumescent [1] cable coating. ... Fireproofing, a passive fire protection measure, subject to bounding, refers to the act of making materials or structures more resistant to fire, or to those materials themselves. ... Firestop after fire exposure during fire test in Tulsa, Oklahoma. ... Fibrous asbestos on muscovite Asbestos Asbestos Asbestos (a misapplication of Latin: asbestos quicklime from Greek : a, not and sbestos, extinguishable) describes any of a group of minerals that can be fibrous, many of which are metamorphic and are hydrous magnesium silicates. ... Expanded Perlite Perlite is an amorphous volcanic glass that has a relatively high water content. ... Sodium silicate, also known as water glass or liquid glass, available in aqueous solution and in solid form, is a compound used in cements, passive fire protection, refractories, textile and lumber processing. ... Gypsum based plaster used in spray fireproofing in a low-rise industrial building in Vancouver, British Columbia. ... Gem animals. ... Square Foot Gardening is a type of intensive gardening popularized by Mel Bartholemew. ...

External links

• United States Senator Patty Murray
• Environmental Working Group
• United States Environmental Protection Agency
• The Vermiculite Association [4]
• The Perlite Association [5]