The single-crystal elastic moduli of lawsonite [CaAl2(Si2O7)(OH)2̇H2 O] were measured by Brillouin spectroscopy at ambient conditions. The Voigt-Reuss-Hill averaged aggregate elastic moduli are KS = 125(2) GPa and μ = 52(2) GPa, for the adiabatic bulk modulus and shear modulus, respectively. Our acoustic results resolve discrepancies between the bulk moduli obtained in earlier compression studies. Lawsonite has distinctive acoustic properties, being characterized by extremely high shear elastic anisotropy (74%), a high VP to VS ratio (VP/VS = 1.94), and a large Poisson's ratio (σ = 0.318).
ASJC Scopus subject areas
- Geochemistry and Petrology