Rubber

 rubber, elastic substance obtained from the exudations of certain tropical plants (natural rubber) or derived from petroleum and natural gas (synthetic rubber). Because of its elasticity, resilience, and toughness, rubber is the basic constituent of the tires used in automotive vehicles, aircraft, and bicycles.More than half of all rubber produced goes into automobile tires; the rest goes into mechanical parts such as mountings, gaskets, belts, and hoses, as well as consumer products such as shoes, clothing, furniture, and toys.The main chemical constituents of rubber are elastomers, or “elastic polymers,” large chainlike molecules that can be stretched to great lengths and yet recover their original shape. The first common elastomer was polyisoprene, from which natural rubber is made. Formed in a living organism, natural rubber consists of solids suspended in a milky fluid, called latex, that circulates in the inner portions of the bark of many tropical and subtropical trees and shrubs, but predominantly Hevea brasiliensis, a tall softwood tree originating in Brazil. Natural rubber was first scientifically described by Charles-Marie de La Condamine and François Fresneau of France following an expedition to South America in 1735. The English chemist Joseph Priestley gave it the name rubber in 1770 when he found it could be used to rub out pencil marks. Its major commercial success came only after the vulcanization process was invented by Charles Goodyear in 1839.

Natural rubber continues to hold an important place in the market today; its resistance to heat buildup makes it valuable for tires used on racing cars, trucks, buses, and airplanes. Nevertheless, it constitutes less than half of the rubber produced commercially; the rest is rubber produced synthetically by means of chemical processes that were partly known in the 19th century but were not applied commercially until the second half of the 20th century, after World War II. Among the most important synthetic rubbers are butadiene rubber, styrene-butadiene rubber, neoprene, the polysulfide rubbers (thiokols), butyl rubber, and the silicones. Synthetic rubbers, like natural rubbers, can be toughened by vulcanization and improved and modified for special purposes by reinforcement with other materials.

Essential properties of the polymers used to produce the principal commercial rubbers are listed in the table🧤🧤🧤

Tiles

 Tiles are usually thin, square or rectangular coverings manufactured from hard-wearing material such as ceramic, stone, metal, baked clay, or even glass. They are generally fixed in place in an array to cover roofs, floors, walls, edges, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite, wood, and mineral wool, typically used for wall and ceiling applications. In another sense, a tile is a construction tile or similar object, such as rectangular counters used in playing games (see tile-based game). The word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of fired clay.Tiles are often used to form wall and floor coverings, and can range from simple square tiles to complex or mosaics. Tiles are most often made of ceramic, typically glazed for internal uses and unglazed for roofing, but other materials are also commonly used, such as glass, cork, concrete and other composite materials, and stone. Tiling stone is typically marble, onyx, granite or slate. Thinner tiles can be used on walls than on floorswhich require more durable surfaces that will resist impacts.

Global production of ceramic tiles, excluding roof tiles, was estimated to be 12.7 billion m2 in 2019.A tile is a manufactured piece of hard-wearing material such as ceramic, stone, porcelain, metal or even glass. Tiles are generally used for covering roofs, floors and walls. They have been made for thousands of years.Tiles can be simple square tiles or arranged in complex mosaics. Tiles are most often made from ceramic, with a hard glaze finish.

At the end of the 20th century, the technology of porcelain and glass tiles advanced, making them cheaper. They became more commonplace🧱🧱🧱

Marbles

 marble, granular limestone or dolomite (i.e., rock composed of calcium-magnesium carbonate) that has been recrystallized under the influence of heat, pressure, and aqueous solutions. Commercially, it includes all decorative calcium-rich rocks that can be polished, as well as certain serpentines (verd antiques).Science

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marble

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marble, granular limestone or dolomite (i.e., rock composed of calcium-magnesium carbonate) that has been recrystallized under the influence of heat, pressure, and aqueous solutions. Commercially, it includes all decorative calcium-rich rocks that can be polished, as well as certain serpentines (verd antiques).

marble quarry

marble quarry

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Related Topics: Parian marble Pentelic marble calcite marble Carrara marble onyx marble

Petrographically marbles are massive rather than thin-layered and consist of a mosaic of calcite grains that rarely show any traces of crystalline form under the microscope. They are traversed by minute cracks that accord with the rhombohedral cleavage (planes of fracture that intersect to yield rhombic forms) of calcite. In the more severely deformed rocks, the grains show stripes and may be elongated in a particular direction or e

ven crushed.Encyclopedia Britannica

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Science

Earth Science, Geologic Time & Fossils

Earth Sciences

marble

rock

Written and fact-checked by 

Article History

marble, granular limestone or dolomite (i.e., rock composed of calcium-magnesium carbonate) that has been recrystallized under the influence of heat, pressure, and aqueous solutions. Commercially, it includes all decorative calcium-rich rocks that can be polished, as well as certain serpentines (verd antiques).

marble quarry

marble quarry

See all media

Related Topics: Parian marble Pentelic marble calcite marble Carrara marble onyx marble

Petrographically marbles are massive rather than thin-layered and consist of a mosaic of calcite grains that rarely show any traces of crystalline form under the microscope. They are traversed by minute cracks that accord with the rhombohedral cleavage (planes of fracture that intersect to yield rhombic forms) of calcite. In the more severely deformed rocks, the grains show stripes and may be elongated in a particular direction or even crushed.

The environmental impact of Carrara's marble quarries

The environmental impact of Carrara's marble quarriesOverview of marble quarrying in Carrara, Italy.

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Marbles often occur interbedded with such metamorphic rocks as mica schists, phyllites, gneisses, and granulites and are most common in the older layers of Earth’s crust that have been deeply buried in regions of extreme folding and igneous intrusion. The change from limestones rich in fossils into true marbles in such metamorphic regions is a common phenomenon; occasionally, as at Carrara, Italy, and at Bergen, Norway, recrystallization of the rock has not completely obliterated the organic structures.

Most of the white and gray marbles of Alabama, Georgia, and western New England, and that from Yule, Colorado, are recrystallized rocks, as are a number of Greek and Italian statuary marbles famous from antiquity, which are still quarried. These include the Parian marble, the Pentelic marble of Attica in which Phidias, Praxiteles, and other Greek sculptors executed their principal works, and the snow-white Carrara marble used by Michelangelo and Antonio Canova and favoured by modern sculptors. The exterior of the National Gallery of Art in Washington, D.C., is of Tennessee marble, and the Lincoln Memorial contains marbles from Yule, Colorado, Alabama (roof transparencies), and Georgia (Lincoln statue).Even the purest of the metamorphic marbles, such as that from Carrara, contain some accessory minerals, which, in many cases, form a considerable proportion of the mass. The commonest are quartz in small rounded grains, scales of colourless or pale-yellow mica (muscovite and phlogopite), dark shining flakes of graphite, iron oxides, and small crystals of pyrite.

Many marbles contain other minerals that are usually silicates of lime or magnesia. Diopside is very frequent and may be white or pale green; white bladed tremolite and pale-green actinolite also occur; the feldspar encountered may be a potassium variety but is more commonly a plagioclase (sodium-rich to calcium-rich) such as albite, labradorite, or anorthite. Scapolite, various kinds of garnet, vesuvianite, spinel, forsterite, periclase, brucite, talc, zoisite, wollastonite, chlorite, tourmaline, epidote, chondrodite, biotite, titanite, and apatite are all possible accessory minerals. Pyrrhotite, sphalerite, and chalcopyrite also may be present in small amounts💎💎💎

Minerals

Minerals are substances that are formed naturally in the Earth. Minerals vary in composition, from pure elements and simple salts to very complex silicates with thousands of known forms. In contrast, a rock sample is a random aggregate of minerals and/or mineraloids, and has no specific chemical composition. Most of the rocks of the Earth's crust have quartz (crystalline SiO2), feldspar, mica, chlorite, kaolin, calcite, epidote, olivine, augite, hornblende, magnetite, hematite, limonite and a few other minerals. Some minerals, like quartz, mica or feldspar are common, while others have been found in only a few places in the world. The largest group of minerals by far is the silicates (most rocks are ≥95% silicates), which are made largely of silicon and oxygen, also with ions of aluminium, magnesium, iron, calcium and other metals.

Rocks are made of minerals. Minerals are usually solid, inorganic, have a crystal structure, and form naturally by geological processes.[1]

The study of minerals is called mineralogy.[2]

A mineral can be made of single chemical element or more usually a compound. There are over 4,000 types of known minerals.[3] Two common minerals are quartz and feldspar🧂🧂🧂