In situ high temperature single crystal X-ray diffraction study of a natural omphacite

Authors: Pavese A.; Bocchio R.; Ivaldi G.

Source: Mineralogical Magazine, Volume 64, Number 6, 1 December 2000 , pp. 983-993(11)

Publisher: Mineralogical Society

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Abstract:

In situ high temperature single crystal X-ray diffraction (XRD) experiments have been performed on a chemically quasi-ideal omphacite sample [(Ca_0.49Na_0.51)₁(Mg_0.46Al_0.48Fe^3.+_0.06)₁(Si_1.97Al_0.03)₂O₆], up to 1000°C. The lattice parameters were studied as a function of temperature, and their thermal expansion coefficients determined. The b and c cell edges show discontinuities as a function of temperature which are interpreted here in terms of intracrystalline cation diffusion processes. Structure refinements have been carried out using data collected at room temperature, at 800°C and at ambient conditions after cooling. The structural behaviour as a function of temperature of chemically quasiideal omphacites is compared with those of jadeite and diopside.

Keywords: OMPHACITES; HIGH; TEMPERATURE; THERMAL; EXPANSION

Language: English

Document Type: Research article

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