Gourt > Science > Earth Sciences > Geology > Rocks and Minerals (27)
Mineral definition and classification
To be classified as a "true" mineral, a substance must be a solid and have a crystal structure. It must also be an inorganic, naturally-occurring, homogeneous substance with a defined chemical composition. The chemical composition may vary between end members of a mineral system. For example the plagioclase feldspars comprise a continuous series from sodium-rich albite (NaAlSi3O8) to calcium-rich anorthite (CaAl2Si2O8) with four recognized intermediate compositions between. Mineral-like substances that don't strictly meet the definition are sometimes classified as mineraloids. Other natural-occurring substances are Nonminerals. Industrial minerals is a market term and refers to commercially valuable mined materials (see also Minerals and Rocks section below).
A crystal structure is the orderly geometric spatial arrangement of atoms in the internal structure of a mineral. There are 14 basic crystal lattice arrangements of atoms in three dimensions, and these are referred to as the 14 "Bravais lattices". Each of these lattices can be classified into one of the six crystal systems, and all crystal structures currently recognized fit in one Bravais lattice and one crystal system. This crystal structure is based on regular internal atomic or ionic arrangement that is often expressed in the geometric form that the crystal takes. Even when the mineral grains are too small to see or are irregularly shaped, the underlying crystal structure is always periodic, and can be determined by X-ray diffraction.
Chemistry and crystal structure together define a mineral. In fact, two or more minerals may have the same chemical composition, but differ in crystal structure (these are known as polymorphs). For example, pyrite and marcasite are both iron sulfide, but their arrangement of atoms differs. Similarly, some minerals have different chemical compositions, but the same crystal structure: for example, halite (made from sodium and chlorine), galena (made from lead and sulfur) and periclase (made from magnesium and oxygen) all share the same cubic crystal structure.
More on [ Mineral ]
Gemstones :: Jewelry
Natural Stone :: Masonry and Stone
Science and Nature :: Recreation
I just downloaded "Chapter 3 Minerals and Rocks" from Docstoc: http://tinyurl.com/y9z8l2n
dnoor (Djauhari Noor) Thu, 17 Dec 2009 05:46:13 -0000
I just downloaded "Chapter 3 Minerals and Rocks" from Docstoc: http://tinyurl.com/y9z8l2n
Minerals, rocks and fossils are for sale by the SNC Geology Club until 2:00 p.m. today. Hurry over to the CC if you're interested.
stnorbert (St. Norbert College) Wed, 16 Dec 2009 19:16:02 -0000
Minerals, rocks and fossils are for sale by the SNC Geology Club until 2:00 p.m. today. Hurry over to the CC if you're interested.
Checkout this great kids book "Rocks and Minerals Spotter's Guide - IR" @ http://www.usbornekidsbooksandmore.com/tw/?459
usbornekidbooks (usbornekidsbooks) Wed, 16 Dec 2009 04:45:52 -0000
Checkout this great kids book "Rocks and Minerals Spotter's Guide - IR" @ http://www.usbornekidsbooksandmore.com/tw/?459
Also a field coming from Earth's crust in rocks with magnetic minerals. This is not included in WMF and IGRF. Enhanced model has this.
theCIRESwire (CIRES Communication) Mon, 14 Dec 2009 18:14:49 -0000
Also a field coming from Earth's crust in rocks with magnetic minerals. This is not included in WMF and IGRF. Enhanced model has this.
Stuff your stockings with great rocks and minerals! www.MiniMeGeology.com Use coupon code ROCK10 for 10% off your entire order.
MiniMeGeology (Tracy Barnhart) Mon, 14 Dec 2009 17:10:59 -0000
Stuff your stockings with great rocks and minerals! www.MiniMeGeology.com Use coupon code ROCK10 for 10% off your entire order.
Checkout this great kids book "100 Rocks and Minerals to Spot - IR" @ http://www.usbornekidsbooksandmore.com/tw/?316
usbornekidbooks (usbornekidsbooks) Sun, 13 Dec 2009 22:00:09 -0000
Checkout this great kids book "100 Rocks and Minerals to Spot - IR" @ http://www.usbornekidsbooksandmore.com/tw/?316
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Bash Rox - Intended for collectors of minerals, rocks and fossils. Features specimen photos and location descriptions and photos, as well as identification guides and links.
Collecting Rocks - USGS information on collecting rocks.
Eastern (USA) Minerals Resources - Gateway to information on minerals and mineral resources research in the eastern United States.
Meta Description: [ USGS Eastern Mineral Resources homepage - gateway to information on minerals and mineral resources research in the eastern United States ]
GeMin Exhibition - GeMin exhibition and online copipes of the Oryktologia NEA news.
Matt's World of Minerals - Site dedicated to the visual learning of Minerals and Geology, containing pictures and information on geology, minerals, and fossils. Also has links to shops, encyclopedias, and a mini-geology database.
Minerals of the United States - Click on the map to view pictures of minerals found in the chosen state.
Meta Description: [ Bob Weaver's U.S. Mineral Collection. This web site has pictures of our personal mineral
collection. Just about all the states have pictures. We also have minerals for sale. ]
Neville R. Hill - A consultant for mining and minerals. He has been published on development of non-metallic rock and mineral resources and building materials production especially in developing countries.
Perlite - Pictures, links, and a brief description of the properties and applications of this siliceous rock.
Rakovan, John - Professor in the Department of Geology at Miami University, Oxford, OH. Includes information on Dr. Rakovan's research and teaching in mineralogy and geochemistry.
Salt (MRBloch Archive) - A collection of material relating to salt [NaCl] and its influence on civilization. Includes sections on physiology, geology, archeology, palaeoclimatology, palaeogeography, production, religion, economics, and etymiology of salt.
Meta Description: [ salting of slaughtered and sacrificed animals, achieved two critical human/animal requirements: physiological,
and use as a preservative. So critical were these two requirements, that a community's Abbatoir soon became its Temple,
and the ceremony of ritual sacrifice to be revered and protected... ]
The Rock, Mineral, and Fossil Reference - Contains over 100 pictures of minerals, rocks and fossils, as well as information about classification, identification, the Science Olympiad Rocks and Minerals event and related topics.
YupRocks - high-resolution pictures of rocks and minerals, taken from personal collections, as well as the Calvin College Geology Department, Michigan, USA.
Meta Description: [ Gallery of rock pictures and mineral pictures taken for the purpose of training others for identification of rock and mineral specimens. ]
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