Agate

Variety names, such as chalcedony and jasper, are given to minute crystalline aggregates of low-temperature quartz. Those showing distinct banding pat- 

Agate that fills the voids in igneous rocks commonly exhibits the following four types of textures see also Fig. 10.18. 

The order of formation of the banding pattern is (1) (4), and there can be cases that all four stages are present, or one part may be absent, or, in some cases, the cycle repeats. 

Bechman and D. R. Hale, Electronic grade synthetic quartz. Brush Strokes, September, 1955,1-7 

Iwasaki and H. Iwasaki, Industrialization of synthetic quartz in the States and Japan, J. Japan. Assoc. Crystal Growth, 25,1988, 247-50 (in Japanese with English abstract) 

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Taking francium as an example, it was assumed that the minute traces of francium ion Fr could be separated from other ions in solution by co-precipitation with insoluble caesium chlorate (VII) (perchlorate) because francium lies next to caesium in Group lA. This assumption proved to be correct and francium was separated by this method. Similarly, separation of astatine as the astatide ion At was achieved by co-precipitation on silver iodide because silver astatide AgAt was also expected to be insoluble. 

Silicon makes up 25.7% of the earth s crust, by weight, and is the second most abundant element, being exceeded only by oxygen. Silicon is not found free in nature, but occurs chiefly as the oxide and as silicates. Sand, quartz, rock crystal, amethyst, agate, flint, jasper, and opal are some of the forms in which the oxide appears. Granite, hornblende, asbestos, feldspar, clay, mica, etc. are but a few of the numerous silicate minerals. 

The reaction proceeds by a free radical chain mechanism involving the following prop agation steps... 

Extensions When more than two conservation equations are to be solved simultaneously, matrix methods for eigenvalues and left eigenvectors are efficient [Jeffrey and Taniuti, Nonlineai Wave Pi op-agation, Academic Press, New York, 1964 Jacob andTondeur, Chem. Eng. J., 22,187 (1981), 26,41 (1983) Davis and LeVan, AJChE J., 33, 470 (1987) Rhee et al., gen. refs.]. 

The PLS calibration set was built mixing in an agate mortar different amounts of Mancozeb standard with kaolin, a coadjuvant usually formulated in agrochemicals. Cluster analysis was employed for sample classification and to select the adequate PLS model acording with the characteristics of the sample matrix and the presence of other components. 

Benzoic acid [65-85-0] M 122.1, m 122.6-123.1, pK 4.12. For use as a volumetric standard, analytical reagent grade benzoic acid should be carefully fused to ca 130 (to dry it) in a platinum crucible, and then powdered in an agate mortar. Benzoic acid has been crystd from boiling water (charcoal), aq acetic acid, glacial acetic acid, C6H6, aq EtOH, pet ether (b 60-80 ), and from EtOH soln by adding water. It is readily purified by fractional crystn from its melt and by sublimation in a vacuum at 80. ... 

Band, m. volume binding.—n. band ribbon, tape, strap, strip, belt, hoop hinge bond, tie, ligament, -achst, m. banded agate, ribbon agate. 

Baum m. tree (Meek.) beam, bar, arbor -achat, m. dendritic agate, moss agate, baum-ahnlich, artig, a. arborescent, tree-lik, Baumaterial, n. building material. 

Blut. n. blood. achst, m. blood agate. ader, /. vein. 

Denaturierung, /. denaturing, denaturation. Denaturierungsmittel, n. denaturant. denaturisieren, v.t. = denaturieren. Dendrachst, Dendritenachst m. dendritic agate. 

Fest-stellung, /. establishing, etc. (see feststellen) statement, -stern, m. fixed star, -stoffgehalt, m. solid content (s). Festungsachat, m. fortification agate, festweich, a. semisolid. 

Jaspachat, m. jasper agate, jasper, jaspiert, p.a. marbled, jasp. ... 

Milch-achat, m. milk-white agate, -ader, /. lacteal vessel. 

Moor-kohle,/. moor coal (black subbituminous coal), -lauge, /. extract from bog earth or peat, -mergel, m. bog marl, -salz, n, salt from peaty soil, -wasser, n. peat water. Moos, n. moss, -achat, m. moss agate, moosartig, a. moss-like, mossy. 

Triimmer, n.pl. fragments fission products remains debris wreck, ruin, -achat, m. brecciated agate, -gestein, n. breccia conglomerate rubble, -masse, /. debris, detritus. 

A. Benzoic acid (C6H5COOH R.M.M. = 122.12). Analytical grade material has a purity of at least 99.9 per cent. For work demanding the highest accuracy, the acid should be dried before use by careful fusion in a platinum crucible placed in an oven at about 130°C, and then powdered in an agate mortar. 

Monochromator 663, 791 Monodentate ligand 51 Morphine (and codeine) D. of (fu) 740 Mortar agate, 155 mullite, 155 percussion, 155 synthetic sapphire, 155 Muffle furnace 97 Multielement analysis 174, 184, 775 Multiple range indicators 268 Murexide 316... 

FIGURE 14.36 Impure forms of silica amethyst (left), in which the color is due to I e impurities agate (center) and onyx (right). 

Grinding conditions are modified by the nature of supports. Gold clusters with a diameter of 1.5 nm were obtained on an aluminum-containing porous coordination polymer by grinding in an agate mortar in air for 20 min, followed by the reduction in a stream of H2 in N2 at 120°C for 2 h ]50]. In contrast, ball milling is favorable... 

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