Any change in the mineral composition of a rock caused by physical or chemical means, especially by hydrothermal fluids. Alteration is milder and more localized than metaporphism.
An analysis of the proportions of metal in an ore. Composition, purity, weight, or other properties of economic interest are tested.
The average quantity or percentage of ore mineral content in an ore body.
A common and chemically active metal (it oxidizes or corrodes easily) - lead ot copper for example.
The process that produces coal of increased rank.
The mass or weight of a substance per volume that it occupies.
The process by which elements move away from the enriched ore zone.
The process by which limestone is converted to dolomite by the replacement of calcium carbonate by magnesium carbonate.
Oxidation potential; the potential of a half-cell, measured against the standard hydrogen half-cell.
An ore deposit that originates later than the enclosing host rocks.
The chemical product of exhalation; a deposit formed by the interaction of volcanically derived water and sea water with subjacent rocks.
Valueless rock or mineral aggregates in an ore; economically undesirable.
A petroluem field containing 500 million barrels or more of recoverable oil; a natural gas field which has a minimum of 3.5 trillion cubic feet of recoverable gas.
An iron-bearing weathered product overlying a sulfide deposit.
A coal classification based on degree of purity.
Pertaining to hot water, the action of hot water, or the products of hot water. The term is generally used for all hot water whether or not the water is of magmatic origin.
The process of practically simultaneous solution and deposition of a new mineral in an old mineral by means of interstitial fluids. The replacement occurs at constant volume with little disturbance of structural or textural features.
A relatively mobile element whose geochemical properties are used to more easily find a deposit of greater importance or value.
The negative log10 of the hydrogen-ion activity in solution; a measure of the acidity or basicity of a solution.
An igneous rock that contains phenocrysts in a fine-grained matrix.
Gold, Silver or minerals of the platinum group.
Introduction of, or replacement by, pyrite, a common process of hydrothermal alteration.
The degree of progressive diagenesis or metamorphism of peat (coalification)
A solid-state change in composition of a mineral accomplished by diffusion of a new material in and an old material out.
Deposits that are economically available and may be extracted profitably with existing technology; a subset of resources.
Naturally occuring deposits in such amounts or concentrations to be minable now or in the future, including reserves.
The introduction of, or replacement by, silica.
Silicate rocks of complex metamorphic-metasomic mineralogy formed in carbonate rocks in a contact metamorphic aureole.
The ratio between the density of a substance and the density of water.
Extraction of ore in an underground mine by working laterally in a series of levels in the plane of the vein.
A mineral deposit confined to a single stratigraphic unit.
A special type of stratabound deposit in which the ore constitutes a layer or layers in the rock.
A near-surface process of mineral deposition in which metals are leached by acidic solutions, carried downward, and re-precipitated, enriching the sulfide minerals already present.
A mineral deposit formed contemporaneously with, and by the same processes as, the enclosing rocks.