Minerals quartz

Shikazono, N. and Nagayama, T. (1993) Origin and depositional mechanism of the Hishikari gold-quartz mineralization. Resource Geology Special Issue, 14, 47-56. 

As a second example, we choose quartz (or any silica polymorph) as a component for a system containing an aqueous fluid and quartz. Now the mole number for the quartz component includes not only the silica in the quartz mineral, the real quartz, but the silica in solution in species such as SiC>2(aq) and IGSiO. Again, the mole numbers of component quartz and real quartz are not the same. A common mistake in geochemical modeling is confusing the components used to describe the composition of a system with the species and phases that are actually present. 

Selected values of (1000 A)1/2 for quartz = mineral lsO, and pyrite = mineral 34S equilibria are found in Table 9.2. In other cases, especially at lower temperature, the temperature dependence of IE s on mineral formation may be more complicated and require empirical fits of the form, in a = Ci/T + C2/T2 or in a = Co + Ci/T + C2/T2, the C s are empirical least squares fitting parameters. 

Figure 11.30 Reduced partition function for various minerals calulated by Kieffer (1982) through equation 11.61 plotted against T. Heavy curve labeled H20(l) is reduced partition function of water according to Becker (1971). Dashed curve is a extrapolation of high-r reduced partition curve for quartz. Mineral abbreviations Qtz (quartz), Calc (calcite), Albt (albite), Muse (muscovite), Enst (clinoenstatite), Anor (anorthite). Diop (diopside), Pyrp (pyrope), Gros (grossular), Zron (zircon), Fors (forsterite), Andr (andra-dite), Rutl (rutile). Reprinted with permission from Kieffer (1982), Review of Geophysics and Space Physics, 20, 827-849, copyright 1982 by the American Geophysical Union.

Table 11.12 Oxygen isotope fractionation in quartz-mineral, mineral-water, and calcite-mineral couples, according to modified increment method of Zheng (1991, 1993a,b).

Mineral Quartz-Mineral Mineral-Water Calcite-Mineral... 

Transparent vitreous sihca is made by electric melting of natural quartz minerals such as sand in vacuum. It also may be made by fusing quartz in flame or by vapor phase hydrolysis or oxidation of pure silicon compounds by heating electrically or using a flame or plasma. Translucent form is made by fusion of high purity quartz sand crystals. 

Transparent Vitreous Silica. Clear, transparent, bubble-free vitreous silica maybe obtained by melting natural quartz minerals, ie, fused quartz, by flame or plasma vapor deposition (synthetic fused silicas), and by sol—gel processing. 

The inadvertent activation of a mineral can often result in an undesirable response to flotation. A typical example is quartz, a highly unreactive mineral whose recovery by flotation is therefore difficult. However, in the presence of metal cations, it can be activated to respond to anionic collectors, as shown by the data13 in Figure 3. It is of interest that the pH value at which flotation is effective can be related to that at which the monohydroxy complexes of the metal ions are predominantly stable, suggesting a specific adsorption of these species onto the quartz surface. In some cases this can be used for the selective depression of the quartz minerals in, for example, the flotation of pyrite in the presence of cationic collectors such as the long-chain amines. 

Fig. 1 Quartz minerals consisting of covalently linked silicon-oxide tetrahedra that are corner-connected and twisted in a helical fashion around three- and six-fold screw axes, rendering individual quartz crystals chiral...

It is easier to analyze quartz petrographically if the sample has been cleaned up by dissolving the non-quartz minerals in hot phosphoric acid. Petrographic analysis can be used to check the phosphoric acid residue produced in the N. A. Talvitie (45) method for the gravimetric examination of quartz. If the residue is not examined petrographically, the reported results may be high. 

The purifications of the dolomite and quartz minerals were investigated by x-ray diffractometer. The results of the x-ray spectra of minerals are given in Fig 2. 

According to the JCPDS- International Center for Diffraction Data in the part of Inorgamc Phases, it was identified that the example of quartz mineral is synthetic quartz with PDF number 33-1161. The example of dolomite is synthetic Dolomite with PDF number 36-426 and a little amount of synthetic Calcite with PDF number 5-586. 

Scratch, R.B., Watson, G.P., Kerrich, R. Hutchinson, R.W. (1984) Fracture controlled antimony-quartz mineralization. Lake George Deposit, New Brunswick mineralogy, geochemistry, alteration, and hydrothermal regimes. Econ. Geol. Bull. Soc. Econ. Geol., 79, 1159-1186. 

For the precise AMS analysis of Be and A1, Hunt et al. (2008) reported an efficient sample preparation method, where quartz was separated from rocks following a sequence of pulverization, size fractionation, acid etching and leaching, and liquid density separation. This protocol yields pure quartz mineral phase, however, trace-level contamination is expected. Most of the time quartz is contaminated due to lattice imperfections with some combination of native Al, Fe, Ti, alkalis, and alkaline earth metals. 

Seawater contains only 2-14 ppm of SiOj and is far below saturation with respect to amorphous silica (34). Part of this is suspended fragments of siliceous organisms (35). Siever has pointed out that the major mechanism for the predpitation of silica on the surface of the earth is biochemical (36). The various organisms responsible for silica deposition were reviewed by Voronkov, Zelchan, and Lukevits (4a). The microcrystalline quartz minerals jasper and chalcedony are probably transformation products of very early diatomite deposits. About two-thirds of the deposited silica is from diatoms and the remainder from radiolaria and sponges. 

Most alumino-silicates, including clays and pillared clays, quartz minerals and oil reservoir sands, possess surfaces which are completely hydrophilic. A common property of such surfaces is their decreasing affinity for alcohols with increasing size of the alkyl group. Thus for kaolinite and an oil reservoir sand the heats of... 

Quartz is estimated to occupy circa 12 % of the earth s crust, so it is not surprising that research into its diverse applications has been of major interest for over 100 years. Important uses are made of quartz minerals that range from piezoelectric devices to the literal down-to earth quartz aggregates required by the construction industry. During the past (1950 s and 60 0s, there were commercial demands for quality quartz crystal required in the manufacture of medical and aerospace sensors (Moxon, 2004 Moxon Carpenter, 2009). 

The density of quartz mineral was determined by adding a weighed piece to a graduated cylinder containing 51.2 mL water. After the quartz was submerged, the water level was 65.7 mL. The quartz piece weighed 38.4 g. What was the density of the quartz ... 

OSL dating is predicated on measurements of a specific mineral and particle size, usually quartz or potassium feldspar. Mineral separations are performed by standard techniques using heavy liquids and hydrofluoric acid (HF) to digest non-quartz minerals and etch the outer 10-20 pm of quartz grains, which are affected by alpha radiation. The purity of the quartz extract is primal for effective dating because a small amount contamination (1 %) by potassium... 

Quartz (mineral) A natural crystalline mineral that undergoes several transformations on... 

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