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 ]

Metals and Minerals - Twitter Search

metals and minerals volatile trading bring it up xra http://bit.ly/1Eldic
yourwinner (Steven) Fri, 06 Nov 2009 15:11:23 -0000
metals and minerals volatile trading bring it up xra http://bit.ly/1Eldic
ບໍຣິສັດ MMG ຈະລົງທຶນຂຍາຍ ບໍ່ທອງແດງເຊໂປນ: ບໍຣິສັດຂຸດຄົ້ນ ບໍ່ແຮ່ MMG ຫລື Minerals and Metals Group ຂອງ ອອສເຕຣເລັຍ.. http://twurl.nl/y8mtyj
laonews (ຂ່າວ ລາວ) Thu, 05 Nov 2009 18:43:16 -0000
ບໍຣິສັດ MMG ຈະລົງທຶນຂຍາຍ ບໍ່ທອງແດງເຊໂປນ: ບໍຣິສັດຂຸດຄົ້ນ ບໍ່ແຮ່ MMG ຫລື Minerals and Metals Group ຂອງ ອອສເຕຣເລັຍ.. http://twurl.nl/y8mtyj
http://twitpic.com/odbhp - Every American born will need 3.6 million pounds of minerals, metals and fuels in their lifetime
OverlandConvey (Overland Conveyor Co) Thu, 05 Nov 2009 16:32:40 -0000
http://twitpic.com/odbhp - Every American born will need 3.6 million pounds of minerals, metals and fuels in their lifetime
Minerals and Metals Group (MMG) says it will spend $US88.1 million ($A97.4 million) on three majo.. http://tinyurl.com/yknczjn #mining #gold
Mining_News (Miningne.ws) Wed, 04 Nov 2009 13:36:44 -0000
Minerals and Metals Group (MMG) says it will spend $US88.1 million ($A97.4 million) on three majo.. http://tinyurl.com/yknczjn #mining #gold
National: MMG to spend $US88.1m on major projects: Minerals and Metals Group (MMG) says it will spend $US88.1 millio... http://bit.ly/21RO8w
smh_news (smh_news) Wed, 04 Nov 2009 09:19:06 -0000
National: MMG to spend $US88.1m on major projects: Minerals and Metals Group (MMG) says it will spend $US88.1 millio... http://bit.ly/21RO8w
http://bit.ly/6I6NZ MMG to spend $US88.1m on major projects: Minerals and Metals Group (MMG).. http://bit.ly/21RO8w
sydney_news2 (sydney_news2) Wed, 04 Nov 2009 09:03:26 -0000
http://bit.ly/6I6NZ MMG to spend $US88.1m on major projects: Minerals and Metals Group (MMG).. http://bit.ly/21RO8w

Subscribe to Metals_and_Minerals RSS feed