Research Results For 'Hydrothermal'

APOPHYLLITE

Apophyllite (so called from its foliated structure or easy cleavage), also called fish-eye stone is a hydrothermal mineral filling cavities in basalt and tufaceous rocks. It is associated with stilbite, scolecite, calcite, prehnite, analcime. It has the formulae KCa4Si8O2O(OH)ù8H2O and a relative hardness of 5.
Research Apophyllite

BARITE

Barite or baryte is major ore of barium. It has a high specific gravity for a light coloured mineral and is a common gangue mineral in hydrothermal veins or as a replacement mineral in veins of limestone and dolomite. It is associated with lead, silver and antimony sulphides. It has the formulae BaSO4 and a relative hardness of 3. It was the first mineral to be found to be luminescent when heated, and led to the discovery of the luminescence of minerals. It is used as an ore of barium, for refining sugar, in the paper industry and as a pigment.
Research Barite

COLEMANITE

Colemanite, named after W.T. Coleman of San Francisco, is a hydrous borate of lime occurring in transparent colourless or white crystals, also massive, in Southern California. It is a major source of borax and has a relative hardness of 5. It occurs in high temperature hydrothermal veins or disseminated in metamorphic rocks associated with other cobalt and nickel sulphides/arsenides.
Research Colemanite

DANALITE

Danalite is a mineral of the helvite group found mainly in granite pegmatite and in hydrothermal veins. Danalite was first discovered at Rockport, Cape Ann, Massachusetts and was confirmed as a distinct species in 1866 and was named in honour of James Dana, a mineralogist at Yale University. Danalite is an iron-rich mineral and appears in octahedra, dodecahedra and as granular masses, and is grey, yellow, red or brown in colour with a vitreous or resinous lustre.
Research Danalite

HUMITE

Humite, named after the English mineralogist Sir Abraham Hume, is a fairly rare mineral of a transparent vitreous brown colour, found in the ejected masses of Vesuvius and in hydrothermal veins. It is a silicate of iron and magnesia, containing fluorine. Humite was confirmed as a distinct species of mineral in 1813.
Research Humite

HYDROTHERMAL

Hydrothermal refers to the alteration of minerals or rocks by super-heated mineral rich fluids, usually water, within a crystallizing magma.
Research Hydrothermal

MENDIPITE

Mendipite is a rare white, grey or colourless mineral with a high density but low relative hardness of 2.5 Mendipite is a halide of lead formed around volcanic vents and in hydrothermal veins. It is most commonly found in association with calcite, cerussite, malachite, manganite, pyrolusite and pyromorphite. Most deposits take the form of columnar or fibrous masses, often with radiating external shapes.
Research Mendipite

METAMORPHIC ROCK

Metamorphic rock is rock that has been altered by intense heat, pressure, or both. It may originally have been sedimentary or igneous rock, or even different metamorphic rock. The changes that take place during metamorphism can affect both the structure of the rock and its composition. Very often the rock is re-crystallized. Contact metamorphism is a localized form of metamorphism that is produced by the heat of an igneous intrusion. Limestone may then be altered into marble, and clay into a hard, tough rock (a hornfels). The zone affected in this way is called a metamorphic aureole. Hydrothermal metamorphism, or metasomatism, is produced by hot aqueous fluids emanating from igneous intrusions. China clay is produced in this way from granite. In dynamic metamorphism, or cataclasis, rocks are broken down mechanically by shearing and crushing; mylonite, a fine-grained banded rock, is a typical product. Regional metamorphism takes place on a large scale. The rocks are subjected to heat, deformation, and the action of hot fluids
that may affect their chemical composition. In the lowest grades of regional metamorphism, slates and phyllites (the latter with better- developed crystals than slate) are formed. More intense regional metamorphism results in the development of schists, rocks with a characteristic wavy foliation. At the highest grades, gneisses are formed: coarsely crystalline rocks with alternate light and dark bands. The normal sequence, from lower to higher metamorphic grade, is known as prograde metamorphism. The process can be reversed if, for example, rocks of a high grade are subsequently maintained for a long time at a lower temperature than was reached during the first metamorphism. Alteration from a higher to a lower grade is termed retrograde metamorphism.
Research Metamorphic Rock

PECTOLITE

Pectolite is a brittle mineral, a hydrous silicate of sodium and calcium with the formulae NaCa2Si3O8(OH) and a relative hardness of 5. It is formed from hydrothermal solutions filling cavities in basalts. Pectolite was confirmed as a distinct species in 1828 and is associated with zeolites, prehnite and calcite.
Research Pectolite

PHILLIPSITE

Phillipsite has the formulae (K2,Na2Ca)(Al2Si4)O12ù4-5H2O and a relative hardness of 5. It is a hydrothermal mineral found lining cavities in basalt rocks associated with chabazite. Formed as an alteration product of feldspars and volcanic ashes.
Research Phillipsite

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