Elasticity of single-crystal calcite and rhodochrosite by Brillouin spectroscopy

Abstract

The single crystals of both calcite and rhodochrosite used in the present work are natural samples. The calcite sample is Iceland spar and the pink rhodochrosite is from an unspecified locality in Mexico. The chemical composition of the latter was confirmed by electron probe analysis [(Mn 0.98 Mg 0.01 Ca 0.01 )CO 3 ]. Both samples can be readily oriented using crystal morphology. ABSTRACTThe single-crystal elastic moduli of natural samples of both calcite (CaCO 3 ) and rhodochrosite (MnCO 3 ) have been measured by Brillouin spectroscopy under ambient condition. GPa for CaCO 3 and MnCO 3 , respectively. Our data for calcite are in good agreement with earlier data obtained by ultrasonic experiments. The off-diagonal elastic constants (C 12 , C 13 , and C 14 ) for rhodochrosite have systematically larger values than the trend defined by other isostructural carbonates, in all of which the divalent cations are alkaline-earth metals. This is a distinctive signature of transition-metal-bearing oxides, which is present in silicates and simple oxides as well.

The crystal data and stability of calcite III at high pressures based on single-crystal X-ray experiments

“…The volume compression data from piston cylinder experiments up to 4.0 GPa by Singh and Kennedy (1974), and the relative volume of calcite II at 1.5 GPa obtained using powder X ray diffraction by Merrill and Bassett (1975) are also given in Figure 1 for comparison. A Birch Murnaghan fitting of the present data for calcite listed in Table 1, with a fixed K0 = 4, yields the bulk modulus at ambient conditions K0 = 75 GPa, which compares well with the reported value of 71 GPa by Singh and Kennedy (1974), and the values, 73 76 GPa, obtained from the measured elastic constants of calcite (Chen et al, 2001, and references therein). Combining the present Birch Murnaghan equation for calcite with the measured volume of calcite II at 1.5 GPa (236.9 A 3 ; see Table 1), we find the volume difference between calcite and calcite II to be 0.54 cm Merrill and Bassett (1975) overestimates considerably the volume of calcite II at 1.5 GPa, compared with our data, as shown in Table 1 and Figure 1.…”

“…This is contrary to a general trend that a denser high pressure phase is less compressible than its lower pressure phase. However, we note aragonite, a high pressure phase of calcite, is again more compressible than calcite; K0 = 65.4(5) GPa for aragonite (Martinez et al, 1996) and K0 = 73 76 GPa for calcite (Chen et al, 2001, and references therein).…”

Single-crystal elasticity of SrCO3 by Brillouin spectroscopy

“…A number of studies have investigated the thermo-elastic properties of calcite-structured carbonates [3][4][5][6][7][8][9][10]. In contrast, the elasticity of aragonite-group minerals has been investigated only in two experimental studies of natural aragonite: Voigt [11], who determined the elastic coefficients with ultrasonic interferometry and Liu et al [12], who measured the elastic coefficients with Brillouin spectroscopy.…”

Higher Order Elastic Constants, Gruneisen Parameters and Lattice Thermal Expansion of Trigonal Calcite

“…1 The trigonal class of crystals has seven second-order elastic constants and fourteen third-order elastic constants. Thermal expansion and elastic properties of single crystal calcite are extensively studied using ultrasonic techniques [2][3][4][5] using Brillouin spectroscopy 6 and using other techniques. [7][8][9][10][11][12] In the present study we make an attempt to calculate the complete set of second and third-order elastic constants, pressure derivatives of the second-order elastic constants, generalized Gruneisen parameters of elastic waves and low temperature thermal expansion of trigonal calcite and are compared with those obtained by other workers.…”

“…[7][8][9][10][11][12] In the present study we make an attempt to calculate the complete set of second and third-order elastic constants, pressure derivatives of the second-order elastic constants, generalized Gruneisen parameters of elastic waves and low temperature thermal expansion of trigonal calcite and are compared with those obtained by other workers. 2,[4][5][6][10][11][12] Higher order elastic constants of calcite.…”