Search results
Results From The WOW.Com Content Network
Fossil skeletal parts from extinct belemnite cephalopods of the Jurassic – these contain mineralized calcite and aragonite.. Biomineralization, also written biomineralisation, is the process by which living organisms produce minerals, [a] often resulting in hardened or stiffened mineralized tissues.
In the context of nutrition, a mineral is a chemical element. Some "minerals" are essential for life, but most are not. [ 1 ] [ 2 ] [ 3 ] Minerals are one of the four groups of essential nutrients; the others are vitamins , essential fatty acids , and essential amino acids . [ 4 ]
Osmium (from Ancient Greek ὀσμή (osmḗ) 'smell') is a chemical element; it has symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores.
Technical grade sheet mica is used in electrical components, electronics, atomic force microscopy and as window sheets. Other uses include diaphragms for oxygen-breathing equipment, marker dials for navigation compasses, optical filters , pyrometers , thermal regulators, stove and kerosene heater windows, radiation aperture covers for microwave ...
Carbonated calcium-deficient hydroxyapatite is the main mineral of which dental enamel and dentin are composed. Hydroxyapatite crystals are also found in pathological calcifications such as those found in breast tumors , [ 8 ] as well as calcifications within the pineal gland (and other structures of the brain) known as corpora arenacea or ...
The scientific definition of a "crystal" is based on the microscopic arrangement of atoms inside it, called the crystal structure. A crystal is a solid where the atoms form a periodic arrangement. (Quasicrystals are an exception, see below). Not all solids are crystals.
A crystalline solid: atomic resolution image of strontium titanate.Brighter spots are columns of strontium atoms and darker ones are titanium-oxygen columns. Octahedral and tetrahedral interstitial sites in a face centered cubic structure Kikuchi lines in an electron backscatter diffraction pattern of monocrystalline silicon, taken at 20 kV with a field-emission electron source
The atomic packing factor is the proportion of space filled by these spheres which can be worked out by calculating the total volume of the spheres and dividing by the volume of the cell as follows: A P F = N p a r t i c l e V p a r t i c l e V unit cell {\displaystyle \mathrm {APF} ={\frac {N_{\mathrm {particle} }V_{\mathrm {particle} }}{V ...