Magma

the fluid rock beneath the Earth's surface, which solidifies to form IGNEOUS ROCKS. During volcanic eruptions, the LAVA extruded at the Earth's surface is not necessarily the same in composition as the magma that arises to form lava, since the magma may have lost some of its gaseous elements and some solids of the magma may have crystallized.

Taken from Dictionary of Science

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Magma [from Greek μάγμα, paste] is molten rock that is found beneath the surface of the Earth, and may also exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma often collects in a magma chamber inside a volcano. Magma is capable of intrusion into adjacent rocks, extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock.

Magma is a complex high-temperature fluid substance. Temperatures of most magmas are in the range 700°C to 1300°C (or 1300°F to 2400°F), but very rare carbonatite melts may be as cool as 600°C, and komatiite melts may have been as hot as 1600°C. Most are silicate solutions.

Environments of magma formation and compositions are commonly correlated. Environments include subduction zones, continental rift zones, mid-oceanic ridges, and hotspots, some of which are interpreted as mantle plumes. Despite being found in such widespread locales, the bulk of the Earth's crust and mantle is not molten. Rather, most of the Earth takes the form of a rheid, a form of solid that can move or deform under pressure. Magma, as liquid, preferentially forms in high temperature, low pressure environments within several kilometers of the Earth's surface.

Magma compositions may evolve after formation by fractional crystallization, contamination, and magma mixing. By definition, all igneous rock is formed from magma.

While the study of magma has historically relied on observing magma in the form of lava outflows, magma has been encountered in situ three times during drilling projects—twice in Iceland, and once in Hawaii.

Taken from Wikipedia

Kaolinite

aluminium silicate with water in its structure which occurs as an alteration product in IGNEOUS ROCKS, GNEISSES and a weathering and hydrothermal reaction product in sedimentary products. It is used in ceramics and as a coating and filler in the paper industry.

Taken from Dictionary of Science

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Kaolinite is a clay mineral with the chemical composition Al₂Si₂O₅(OH)₄. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra. Rocks that are rich in kaolinite are known as china clay, white clay, or kaolin.

The name is derived from Gaoling or Kao-Ling (高嶺; "High Hill") in Jingdezhen, Jiangxi province, China. Kaolinite was first described as a mineral species in 1867 for an occurrence in the Jari River basin of Brazil.

Kaolinite has a low shrink-swell capacity and a low cation exchange capacity (1-15 meq/100g.) It is a soft, earthy, usually white mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. In many parts of the world, it is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lighter concentrations yield white, yellow or light orange colours. Alternating layers are sometimes found, as at Providence Canyon State Park in Georgia, USA.

Taken from Wikipedia

Ultrabasic Rock

an IGNEOUS ROCK that contains many silicate minerals of iron and magnesium such as AMPHIBOLES and PYROXENES, and with SILICA occurring as quartz.

Taken from Dictionary of Science

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An igneous rock with a very low silica content and rich in minerals such as hypersthene, augite and olivine. These rocks are also known as ultramafic rocks.

Taken from Geology.com