Grossular garnet

Narrow lines at 462, 476, 482, 501 and 590 nm in the luminescence spectrum of the Ca-variety of garnet (grossular) with a relatively short decay time are not typical for traditional trivalent REE in minerals. Evidently they may be connected to visible emission of Nd (Fig. 4.57c,d), but this has to be checked. 

Broadband LIBS spectra for three garnet types - the Mg-AI pyrope type, the Ca-AI grossular type, and the Mn-AI spessartine type are shown in Figure 1. 

Fig.1. Example broadband LIBS spectra for a pyrope, grossular, and spessartine garnet. The clear differences observed in the broadband spectra reflect the chemical differences in the composition of the three garnets.

Fig. 5. Confusion matrix for the HDPCA analysis of the four grossular garnets. The nth row and column correspond to the nth grossular type truth and HDPCS statistical assignment, respectively.

Bass X D. (1989). Elasticity of grossular and spessartite garnets by Brillonin spectroscopy. J. Geophys. Res., 94 7621-7628. 

Cressey G. (1978). Exsolution in almandine-pyrope-grossular garnet. Nature, 271 533-534. 

Cressey G, Schmid R., and Wood B. I (1978). Thermodynamic properties of almandine-grossular garnet solid solutions. Contrib. Mineral Petrol, 67 397-404. 

Ganguly J., Cheng W., and O Neill H. St. C. (1993). Syntheses, volume, and structural changes of garnets in the pyrope-grossular join Implications for stability and mixing properties. Amer Mineral, 78 583-593. 

Geiger C. A., Newton R. C. and Kleppa O. I (1987). Enthalpy of mixing of synthetic almandine-grossular and almandine-pyrope garnets from high-temperature solution calorimetry. Geochim. Cosmochim. Acta, 51 1755-1763. 

Haselton H. T. and Newton R. C. (1980). Thermodynamics of pyrope-grossular garnets and their stabilities at high temperatures and pressures. J. Geophys. Res., 85 6973-6982. 

Wood B. I (1988). Activity measurements and excess entropy-volume relationships for pyrope-grossular garnets. J. Geol, 96 721-729. 

Direct observation of immiscibility in pyrope-almandine-grossular garnet. 

Garnet Pyrope Mg3Al2(Si04)3 and Grossular Ca3Al2(Si04)3... 

Grossular (Garnet) Simple calcium aluminum silicate Massive green (a.k.a. transvaal j ade ) 1.54-1.55 7 2.6-2.7... 

Jade is the common name for gem-quality specimens of two distinctly different mineral species, jadeite and the massive variety of actinolite, called nephrite. The word jade is derived from the Spanish piedra deyjada, meaning stone of the flank. This refers to its popular use as a cure for diseases of the kidneys and liver. Other minerals that have been mistaken for jade, or used as jade imitations include green jasper (quartz), vesuvian (idocrase), massive grossular garnet, chloromelanite (a mixture of dark pyroxenes) (Table 2.10). 

Several other anhydrous calcium aluminosilicates are known, including grossular or garnet (C3AS3), which is a high-pressure phase, various dehydration products of zeolites, and various products formed metastably by crystallization from melts or glasses. Most are too acid in composition to be of clear relevance to cement chemistry, but some of the devitrification products, especially those with compositions near to CA and structures similar to those of nepheline (Na3KAl4Si40i6) or kalsilite (KAlSiOj (Y4), are of possible interest in relation to the formation of calcium aluminate cements. 

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