George R. Rossman | |
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| Born | 3 August 1944 La Crosse, Wisconsin, U.S. |
| Alma mater | University of Wisconsin–Eau Claire California Institute of Technology |
| Scientific career | |
| Fields | Mineralogy, gemology and inorganic chemistry |
| Institutions | California Institute of Technology |
| Doctoral advisor | Harry B. Gray |
George R. Rossman is an American mineralogist and the Professor of Mineralogy at the California Institute of Technology.
Rossman was born in LaCrosse, Wisconsin, but soon moved to Eau Claire. His father owned a dental laboratory.
Rossman graduated as the salutatorian from high school in Eau Claire. In high school, he participated in the Wisconsin Junior Academy of Science competitions winning first place in the 1961 competition. He attended the Wisconsin State University–Eau Claire (now the University of Wisconsin-Eau Claire) from 1962 to 1966 where he received a Bachelor of Science degree majoring in both Chemistry and Mathematics. He graduated summa cum laude, with honors in Chemistry. From there, he moved to Pasadena, California, where he obtained a PhD in chemistry from California Institute of Technology in 1971. He specialized in inorganic chemistry in the research group of Professor Harry B. Gray. [1]
Immediately upon graduating with his PhD in 1971, he became an instructor in the Division of Geological and Planetary Sciences at Caltech and was soon thereafter appointed assistant professor of Mineralogy and Chemistry. He is now Professor of Mineralogy at Caltech. [2]
At Caltech, Rossman regularly teaches the introductory mineralogy course, a course in mineral spectroscopy, and a course in oral presentation. He supervises the optical mineralogy course, co-teaches analytical methods in Geochemistry, and presents guest lectures in Advanced Inorganic Chemistry. He was recognized by students and faculty with the Richard P. Feynman Prize for Excellence in Teaching. [3]
Rossman studies mineral spectroscopy, water and hydroxide in nominally anhydrous solids, analytical methods for OH analysis in minerals, X-ray amorphous minerals, and the effects of exposure on minerals to background levels of natural radiation. Paul Asimow, describing Rossman's work, wrote, "Within the general rubric of mineral spectroscopy, Rossman's work can be grouped into three principal categories: the origin of color, the effects of natural and artificial radiation damage, and the concentration and crystal chemistry of hydrogen in minerals both hydrous and nominally anhydrous." [4]
Rossman is author or co-author of more than 380 articles on mineralogy, inorganic chemistry, gemology, and materials science.
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.
Tourmaline is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a wide variety of colors.
Hornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rocks.
Brazilianite, whose name derives from its country of origin, Brazil, is a typically yellow-green phosphate mineral, most commonly found in phosphate-rich pegmatites.
Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms a hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are colourless crystals, but samples are often contaminated with iron(III) chloride, giving them a yellow colour.
In chemistry, an aluminate is a compound containing an oxyanion of aluminium, such as sodium aluminate. In the naming of inorganic compounds, it is a suffix that indicates a polyatomic anion with a central aluminium atom.
Akaganeite, also written as the deprecated Akaganéite, is a chloride-containing iron(III) oxide-hydroxide mineral, formed by the weathering of pyrrhotite (Fe1−xS).
Buddingtonite is an ammonium feldspar with formula: NH4AlSi3O8 (note: some sources add 0.5H2O to the formula). It forms by hydrothermal alteration of primary feldspar minerals. It is an indicator of possible gold and silver deposits, as they can become concentrated by hydrothermal processes. It crystallizes in the monoclinic crystal system and is colorless to white with a vitreous luster. Its structure is analogous to that of high sanidine (KAlSi3O8). Buddingtonite has a hardness of 5.5 and a specific gravity of 2.32.
Iron(III) oxide-hydroxide or ferric oxyhydroxide is the chemical compound of iron, oxygen, and hydrogen with formula FeO(OH).
Frank Christopher Hawthorne is a Canadian mineralogist, crystallographer and spectroscopist. He works at the University of Manitoba, Winnipeg, Manitoba, Canada, and is currently Distinguished Professor Emeritus. By combining Graph Theory, Bond-Valence Theory and the moments approach to the electronic energy density of solids he has developed Bond Topology as a rigorous approach to understanding the atomic arrangements, chemical compositions and paragenesis of complex oxide and oxysalt minerals.
In inorganic chemistry, mineral hydration is a reaction which adds water to the crystal structure of a mineral, usually creating a new mineral, commonly called a hydrate.
Ferrihydrite (Fh) is a widespread hydrous ferric oxyhydroxide mineral at the Earth's surface, and a likely constituent in extraterrestrial materials. It forms in several types of environments, from freshwater to marine systems, aquifers to hydrothermal hot springs and scales, soils, and areas affected by mining. It can be precipitated directly from oxygenated iron-rich aqueous solutions, or by bacteria either as a result of a metabolic activity or passive sorption of dissolved iron followed by nucleation reactions. Ferrihydrite also occurs in the core of the ferritin protein from many living organisms, for the purpose of intra-cellular iron storage.
Ringwoodite is a high-pressure phase of Mg2SiO4 (magnesium silicate) formed at high temperatures and pressures of the Earth's mantle between 525 and 660 km (326 and 410 mi) depth. It may also contain iron and hydrogen. It is polymorphous with the olivine phase forsterite (a magnesium iron silicate).
Moganite is an oxide mineral with the chemical formula SiO2 (silicon dioxide) that was discovered in 1976. It was initially described as a new form of silica from specimens found in the Barranco de Medio Almud, in the municipality of Mogán on the island of Gran Canaria, in the Canary Islands (Spain), receiving in a later work the name derived from this locality. In 1994 the International Mineralogical Association decided to disapprove it as a valid mineral, since it was considered indistinguishable from quartz. Subsequent studies allowed the IMA to rectify it in 1999, accepting it as a mineral species. It has the same chemical composition as quartz, but a different crystal structure.
Iron(III) sulfate (or ferric sulfate), is a family of inorganic compounds with the formula Fe2(SO4)3(H2O)n. A variety of hydrates are known, including the most commonly encountered form of "ferric sulfate". Solutions are used in dyeing as a mordant, and as a coagulant for industrial wastes. Solutions of ferric sulfate are also used in the processing of aluminum and steel.
The endmember hornblende tschermakite (☐Ca2(Mg3Al2)(Si6Al2)O22(OH)2) is a calcium rich monoclinic amphibole mineral. It is frequently synthesized along with its ternary solid solution series members tremolite and cummingtonite so that the thermodynamic properties of its assemblage can be applied to solving other solid solution series from a variety of amphibole minerals.
Magmatic water, also known as juvenile water, is an aqueous phase in equilibrium with minerals that have been dissolved by magma deep within the Earth's crust and is released to the atmosphere during a volcanic eruption. It plays a key role in assessing the crystallization of igneous rocks, particularly silicates, as well as the rheology and evolution of magma chambers. Magma is composed of minerals, crystals and volatiles in varying relative natural abundance. Magmatic differentiation varies significantly based on various factors, most notably the presence of water. An abundance of volatiles within magma chambers decreases viscosity and leads to the formation of minerals bearing halogens, including chloride and hydroxide groups. In addition, the relative abundance of volatiles varies within basaltic, andesitic, and rhyolitic magma chambers, leading to some volcanoes being exceedingly more explosive than others. Magmatic water is practically insoluble in silicate melts but has demonstrated the highest solubility within rhyolitic melts. An abundance of magmatic water has been shown to lead to high-grade deformation, altering the amount of δ18O and δ2H within host rocks.
Strashimirite is a rare monoclinic mineral containing arsenic, copper, hydrogen, and oxygen. It has the chemical formula Cu8(AsO4)4(OH)4·5(H2O).
The deep water cycle, or geologic water cycle, involves exchange of water with the mantle, with water carried down by subducting oceanic plates and returning through volcanic activity, distinct from the water cycle process that occurs above and on the surface of Earth. Some of the water makes it all the way to the lower mantle and may even reach the outer core. Mineral physics experiments show that hydrous minerals can carry water deep into the mantle in colder slabs and even "nominally anhydrous minerals" can store several oceans' worth of water.
Robert Day Shannon is a retired research chemist formerly at DuPont de Nemours, Inc.
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