A mixture of two or more metals.
The smallest particle of an element, consisting of protons, neutrons, and electrons. An atom can exist either alone or in combination with other atoms in a molecule.
The joining through electromagnetic force of atoms that sometimes, but not always, represent more than one chemical element.
A substance made up of atoms of more than one element, chemically bonded to one another.
A process whereby materials become compacted, or experience an increase in density.
A type of solid in which the constituent parts have a simple and definite geometric arrangement that is repeated in all directions.
The process wherebysediment is laid down on the Earth's surface.
Capable of being bent or molded into various shapes without breaking.
The study of fuels, metals, and other materials from the earth that are of interest to industry or the economy in general.
A negatively charged particle in an atom, which spins around the nucleus.
Fuel derived from deposits of organic material that have experienced decomposition and chemical alteration under conditions of high pressure. These nonrenewable forms of bioenergy include petroleum, coal, peat, natural gas, and their derivatives.
Minerals of no economicvalue, which appear in nature with ore. Recognition of certain characteristic combinations can help geologists find ore on the basis of its attendant gangue. (The ue issilent, as in tongue. )
In mineralogy, the ability of one mineral to scratch another. This can be measured by the Mohs scale.
Any organic chemical compound whose molecules are madeup of nothing but carbon and hydrogenatoms.
One of the three principal types of rock, along with sedimentary and metamorphic rock. Igneous rock is formed by the crystallization of molten materials, for instance, in a volcano or other setting where plate tectonicprocesses take place.
Nonmetallic minerals with uses for industry.
The appearance of a mineral when light reflects off its surface. Among the terms used in identifying luster are metallic, vitreous (glassy), and dull.
Substances that are ductile, lustrous or shiny in appearance, extremelydurable, and excellent conductors of heat and electricity. Metals have very high melting and boiling points, and some (thoughfar from all) have a high degree of hardness.
One of the three principal varieties of rock, along with sedimentary and igneous rock. Metamorphic rock is formed through the alteration of preexisting rock as a result of changes intemperature, pressure, or the activity offluids. These changes are known as metamorphism.
A naturally occurring, typically inorganic substance with a specific chemical composition and a crystalline structure. Unknown minerals usually can be identified in terms of specific parameters, such as hardness or luster.
An area of geology devoted to the study of minerals. Mineralogy includes a number of subdisciplines, such as crystallography, or the study of crystal formations within minerals.
A scale introduced in 1812 by the German mineralogist Friedrich Mohs (1773-1839) that rates the hardness of minerals from 1 to 10. Ten is equivalent to the hardness of a diamond and 1 that of talc, an extremely soft mineral.
A group of atoms, usually but not always representing more than one element, joined in a structure. Compounds are typically made up of molecules.
The center of an atom, a region where protons and neutrons are located and around which electrons spin.
A metalliferous rock or mineral possessing economic value.
At one time chemists used the term organic only in reference to living things. Now the word is applied to most compounds containing carbon and hydrogen, thus excluding carbonates (which are minerals), and oxides such as carbon dioxide.
The study of the material components of Earth and of the forces that have shaped the planet. Physical geology is one of two principal branches of geology, the other being historical geology.
A positively charged particle in an atom.
An aggregate of minerals or organic matter, which may be consolidated or unconsolidated.
Material deposited at or near Earth's surface from a number of sources, most notably preexisting rock.
One of the three major types of rock, along with igneous and metamorphic rock. Sedimentary rock usually is formed by the deposition, compaction, and cementation of rock that has experienced weathering. It also may beformed as a result of chemical precipitation.
The color of the powder produced when one mineral is scratched byanother, harder one.
Rock that appears in the form of loose particles, such as sand.
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