| 词条 | Gmelinite |
| 释义 |
| name = Gmelinite-Na | category = Zeolites | image = Gmelinite-Na-Chabazite-Ca-153544.jpg | imagesize = 260px | caption = | formula = Na4(Si8Al4)O24·11H2O[1] | molweight = 2,000.77 g | strunz = 9.GD.05 (10 ed) 8/J.26-50 (8 ed) | dana = 77.1.2.6 | system = Hexagonal | class = Dihexagonal dipyramidal (6mmm) H-M symbol: (6/m 2/m 2/m) | symmetry = P63/mmc | unit cell = a = 13.78, c = 10.03 [Å]; Z = 4 | color = Colorless, white, yellow, orange, pale green, pink, red, brown and grey | habit = Hexagonal plates, or short prisms, showing hexagonal dipyramids, pyramids and basal pinacoid. {10{{overline|1}}0}, {10{{overline|1}}1} and {0001} dominant. May also be tabular or rhombohedral. Crystals are striated parallel to (0001) | twinning = Interpenetrant twins common[2] on {10{{overline|1}}1}. The twins consist of four individuals, three are at 90° to the other and at 60° to each other[3] | cleavage = Good on {10{{overline|1}}0} | fracture = Conchoidal | tenacity = Brittle | mohs = {{frac|4|1|2}} | luster = Dull to vitreous | refractive = nω = 1.476 - 1.494, nε = 1.474 - 1.480[2] | opticalprop = Uniaxial (-) | birefringence = δ = 0.002 - 0.014 | pleochroism = | streak = White | gravity = 2.04 to 2.17 | density = | melt = | fusibility = | diagnostic = | solubility = Soluble in cold 10% HCl. | diaphaneity = Transparent, translucent or opaque | other = Piezoelectric. Barely detectable radioactivity. As with all zeolites, water is released on heating, and almost all has been expelled by 400 °C. | references = [3][4] }} Gmelinite-Na is one of the rarer zeolites but the most common member of the gmelinite series, gmelinite-Ca, gmelinite-K and gmelinite-Na. It is closely related to the very similar mineral chabazite. Gmelinite was named as a single species in 1825 after Christian Gottlob Gmelin (1792–1860) professor of chemistry and mineralogist from Tübingen, Germany, and in 1997 it was raised to the status of a series.[5] StructureThe aluminosilicate framework is composed of tetrahedra linked to form parallel double six-membered rings stacked in two different positions (A and B) in the repeating arrangement AABBAABB. The framework has no Al-Si order.[3] Within the structure there are cavities with a cross-section of up to 4 Å, and also wide channels parallel to the c axis with a diameter of 6.4 Å.[6] Space group: P63/mmc. Unit cell parameters:[2] a=13.72 Å, c=9.95 Å, Z=4. EnvironmentGenerally occurs in Si-poor volcanic rocks, marine basalts and breccias, associated with other sodium zeolites such as analcime, Notable localitiesGmelinite-Na occurs extremely rarely at the Francon Quarry, Montreal, Canada, in sills of the igneous volcanic rock phonolite which are rich in dawsonite, NaAl(CO3)(OH)2.[8] It occurs both as pure gmelinite-Na and interlayered with chabazite in water-quenched basalts in Western Tasmania.[9] Associated minerals include other zeolites, especially chabazite, quartz, aragonite and calcite. DistributionType Locality: Monte Nero, San Pietro, Montecchio Maggiore, Vicenza Province, Veneto, Italy. Also found in Australia, Canada, Czech Republic, Germany, Hungary, Japan, Russia, UK and US.[4]References1. ^http://rruff.info/ima 2. ^1 2 Roberts, Campbell and Rapp (1990) Encyclopedia of Minerals, 2nd edition 3. ^http://www.webmineral.com/data/Gmelinite-Na.shtml 4. ^1 http://www.mindat.org/min-6973.html Mindat.org 5. ^1 2 3 4 Deer, Howie and Zussman (2004) Rock-Forming Minerals Volume 4B:690-696 6. ^Senderov and Shishakova (1967) Russian Chemical Bulletin 16-1:151 7. ^1 2 Gaines et al (1997) Dana's New Mineralogy Eighth Edition 8. ^Tarassoff, Peter, and Horvath, Lazlo and Elsa (2006) Mineralogical Record 37-1:35 9. ^Sutherland, F L and Bottrill, R S (2004) Zeolites of Western Tasmania, Australian Journal of Mineralogy 10-2: 59 - 72 External links
5 : Sodium minerals|Calcium minerals|Aluminium minerals|Zeolites|Hexagonal minerals |
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