Synthetic diamond
Synthetic diamond, man-made diamond that is usually produced by subjecting graphite to very high temperatures and pressures. Synthetic diamond resembles natural diamond in most fundamental properties, retaining the extreme hardness, broad transparency (when pure), high thermal conductivity,…
Fracture
Fracture, in mineralogy, appearance of a surface broken in directions other than along cleavage planes. There are several kinds of fractures: conchoidal (curved concavities resembling shells—e.g., flint, quartz, glass); even (rough, approximately plane…
Cleavage
Cleavage, tendency of a crystalline substance to split into fragments bounded by plane surfaces. Although cleavage surfaces are seldom as flat as crystal faces, the angles between them are highly characteristic and…
Intelligent design
Intelligent design (ID), argument intended to demonstrate that living organisms were created in more or less their present forms by an “intelligent designer.” Intelligent design was formulated in the 1990s,…
Intermetallic compound
Intermetallic compound, any of a class of substances composed of definite proportions of two or more elemental metals, rather than continuously variable proportions (as in solid solutions). The crystal structures…
Silicon carbide
Silicon carbide, exceedingly hard, synthetically produced crystalline compound of silicon and carbon. Its chemical formula is SiC. Since the late 19th century silicon carbide has been an important material for sandpapers, grinding wheels, and cutting…
Ductility
Ductility, Capacity of a material to deform permanently (e.g., stretch, bend, or spread) in response to stress. Most common steels, for example, are quite ductile and hence can accommodate local stress concentrations.…
Phosphorus
Phosphorus (P), nonmetallic chemical element of the nitrogen family (Group 15 of the periodic table) that at room temperature is a colourless, semitransparent, soft, waxy solid that glows in the dark. Element Propertiesatomic number15atomic weight30.9738melting point (white)44.1…
Silicon
(Group 14 of the periodic table). Silicon makes up 27.7 percent of Earth’s crust; it is the second most abundant element in the crust, being surpassed only by oxygen. The name silicon derives from…
