Minerals common rock-forming

Aluminosilicates. These silicates consist of frameworks of silica and alumina tetrahedra linked at all corners to form three-dimensional networks familiar examples are the common rock-forming minerals quartz and feldspar. Framework silicates generally form blocky crystals, more isotropic... 

The long history of bestowing names on minerals has provided some confusing legacies. Many mineral names end with the suffix ite, although not most of the common species no standard naming practice has ever been adopted. Occasionally different names have been applied to samples of the same mineral that differ only in color or shape, but are identical to each other in chemical composition and crystal structure. These names, usually of the common rock-forming minerals, are often encountered and are therefore accepted as synonyms or as varieties of bona fide mineral species. The Fibrous Minerals list (Appendix 1) includes synonyms. 

The pyroxenes are chemically complex but common rock-forming minerals. They resemble the amphiboles in many ways, but are actually single-chain silicates. The tetrahedral basic unit of the pyroxenes, [(Al,Si)20g] , was schematically depicted in Fig. 2.1C. The general formula for the group is Ai (B, C)i+ TjOfi, where A = Ca" Fe Li+, Mg "", Na-" B = Mg ", Fe Mn" Sc+ C = Fe A Cr" Ti " and T = Si Al+l Within the group are several mineral series and several species that often occur in acicular or fibrous forms. One species that occurs in fibrous form is jadeite, [Na(Al,Fe )Si206], a relatively familiar name because of the popularity of this material with Oriental sculptors. 

We have recorded 388 minerals (Appendix 1) that occur, at least occasionally, as fibers some minerals are found only in fibrous form. This number includes more than 92 silicate and aluminosilicate species, most of them common rock-forming minerals. This list, only a fraction of the 3000 minerals known, probably represents only a sampling of naturally occurring fibers. 

Although olivine is a common rock-forming mineral and quartz is the commonest of minerals, they are never found together. Explain. 

The slopes of the linear correlation then gives activation energies E = 80 + 4 and 106 4kJ/mol for 4He and 20Ne, for the diffusion coefficient D = D0 exp(-E/RT). It is worth noting that the activation energies are much less than those estimated for olivine, a common rock-forming mineral (see Table 2.8). The time required for a gas... 

With a known mineral, as determined by electron diffraction or other technique (such as X-ray diffraction), determination of the stoichiometry and structural formula can be a suitable test for analytical precision of thin-film elemental analyses. This simple test follows the practice commonly employed for electron microprobe data in which the accuracy (and completeness) of an analysis is judged by the departure from stoichiometry calculated for a given mineral. Thus, thin-film analyses of olivines, pyroxenes, garnets, feldspars and many other common rock-forming minerals can be examined for internal consistency via a calculation of structural formulae. 

Hazen RM (2004) Chiral Crystal Faces of Common Rock-Forming Minerals In Pa-lyi G, Zucchi C (eds) Progress in Biological Chirality chap 9. Elsevier, Oxford, pp 137-151... 

Chapter 5 summarizes the crystal field spectra of transition metal ions in common rock-forming minerals and important structure-types that may occur in the Earth s interior. Peak positions and crystal field parameters for the cations in several mineral groups are tabulated. The spectra of ferromagnesian silicates are described in detail and correlated with the symmetries and distortions of the Fe2+ coordination environments in the crystal structures. Estimates are made of the CFSE s provided by each coordination site accommodating the Fe2+ ions. Crystal field splitting parameters and stabilization energies for each of the transition metal ions, which are derived from visible to near-infrared spectra of oxides and silicates, are also tabulated. The CFSE data are used in later chapters to explain the crystal chemistry, thermodynamic properties and geochemical distributions of the first-series transition elements. 

Inosilicates contain single or double chains of tetrahedra. In a single chain structure, the Si to O ratio is 1 3, and in a double chain, it is 4 11. This structural class contains many common rock-forming minerals, including the amphibole and pyroxene groups. Both jade minerals, jadeite, and nephrite, fall within this group. 

There are 21 different feldspars, most of which are common rock-forming minerals. It is estimated that feldspars make up at least 50% of all the rocks in the Earth s crust. A few members of this group are sometimes used as... 

Although there are more than 2,000 minerals identified, only a few are the most common rock-forming minerals. These are listed in Table 5.1. 

Table 5.1. The most common rock-forming minerals.

Common rock-forming mineral, although most Al-bearing silicates quite insoluble. Potentially soluble Al-hydroxides, hydroxysulfates form in lateric ore deposits, tropical soils, and precipitate in streams affected by acid-rock drainage. Al-rich soluble salts can occur in evaporative lake sediments, and in mine wastes. Potentially reactive forms in cement, concrete, smelter emissions, coal fly ash. 

Feldspar a group of common rock-forming minerals with the general composition MAl(AlSi3)08 where M=K, Na, Ca, Ba, Rb, Sr, or Fe. 

Note The more common rock-forming minerals are italicized (cf. Deer et ai. 1992). Single pATjp values are presumably for well-crystallized, least soluble forms. Where p/T p ranges are given, they reflect the solubility range between relatively amorphous and well-crystallized forms, values have been computed assuming specific solution speciation models (e.g., specific complexes and complex stability constants), which must also be used when these constants are employed in mineral saturation index calculations. 

Table 3.3 Common rock-forming minerals and their distinctive attributes ...

Figure 6,9. Weathering pathways for the common rock-forming minerals of the earth s crust. (Adapted from B. Mason. 1966. Principles of Geochemistry. 3rd ed. New York Wiley.)...

Silicon—Cation Ratios in Solids and Stream Water. During low-flow periods of the Mattole river, the ratio of silicon (equivalents/liter) to alkalis plus alkaline earths (equivalents/liter) in solution is approximately 0.15-0.2, and following high flows it is in the range 0.8-0.9. These ratios can be compared with those in various common rock-forming minerals, as listed in Table IV. 

Table IV. Ratio of Silicon to Alkalis Plus Alkaline Earths in Common Rock-Forming Minerals and Clay Minerals...

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