Physics

Aragonite Definition Aragonite is a usually white, yellowish, or pink orthorhombic mineral that can occur in many different colors. It is a polymorph of calcite,…

Crocoite Definition Crocoite is a rare orange secondary mineral consisting of lead chromate in monoclinic crystalline form. It’s mineral consisting of lead chromate, PbCrO4, that…

Calcite Definition Calcite is a usually white, clear, pale-yellow or blue orthorhombic mineral. Calcite occurs in many different forms and is the main component of…

Holmium Definition Holmium is a soft, silvery, malleable metallic element of the lanthanide series. Its compounds are highly magnetic. Its atomic number 67; atomic weight…

Lanthanum Definition Lanthanum is a soft, malleable, silvery-white metallic element of the lanthanide series. It is the eponym of the lanthanide series, a group of…

Yttrium Definition Yttrium is a silvery metallic element found in the same ores as elements of the lanthanide series. It is almost always found in…

Bastnäsite Definition Bastnäsite is a rare yellow to reddish-brown mineral consisting of a carbonate of fluorine and several lanthanide metals. It occurs in association with…

Neodymium Definition Neodymium is a shiny, silvery metallic element of the lanthanide series. It is present in significant quantities in the ore minerals monazite and…

Scheelite Definition Scheelite is a white, brownish, or greenish mineral, usually fluorescent, consisting of calcium tungstate in tetragonal crystalline form with some tungsten often replaced…

Tungsten Definition Tungsten is a hard, gray to white metallic element that is very resistant to corrosion. It has the highest melting point of all…

Rhenium Definition Rhenium is a very rare, dense, silvery-white metallic element with a very high melting point. It is used to make catalysts and electrical…

Diorite Definition Diorite is a gray, coarse-grained plutonic rock. Diorite consists mainly of sodium-rich plagioclase and one or more mafic minerals such as biotite, hornblende,…