Physics

Chondrite Definition Chondrite is a stony meteorite that contains chondrules embedded in a fine matrix of the silicate minerals olivine and pyroxene. About 85 percent…

Meteorite Definition Meteorite is a meteor that reaches the Earth’s surface because it has not been burned up by friction with the atmosphere. Meteorites are…

Cryolite Definition Cryolite is a white or colourless mineral consisting of a fluoride of sodium and aluminium in monoclinic crystalline form: used in the production…

Fluorite Definition Fluorite (CaF2) is a transparent to translucent mineral occurring in many colors, especially yellow and purple, and usually in cube-shaped crystals with octahedral…

Pyrite Definition Pyrite (FeS2) is a silver to yellow, metallic, cubic mineral. Pyrite often crystallizes in cubes or octahedrons but also occurs as shapeless masses…

Tantalum Definition Tantalum is a hard, heavy, gray metallic element that is highly resistant to corrosion at low temperatures. It is almost immune to chemical…

Pyrochlore Definition Pyrochlore is a complex oxide mineral (Na,Ca)2Nb2O6(OH,F), which is composed of niobium, sodium, and calcium that forms brown to black, glassy octahedral crystals…

Niobium Definition Niobium is a smooth, silvery, ductile metallic component that, together with the element tantalum, typically occurs in nature. It is used for the…

Antimony Definition Antimony is a metalloid element having many forms, the most common of which is a hard, very brittle, shiny, blue-white crystal. Antimony compounds…

Neptunium Definition Neptunium is a silvery, radioactive metallic element of the actinide series. It occurs naturally in minute amounts in uranium ores and is produced…

About Plutonium Definition Plutonium is a silvery, radioactive metallic element of the actinide series that has the highest atomic number of all naturally occurring elements.…

Indium Definition Indium is a soft, malleable, silvery-white metallic element that occurs mainly in ores of zinc and lead. Its atomic number 49; atomic weight…