%************************************************
% Define elastic stiffness tensor (GPa)
%************************************************
%
% Reference Elastic constants
% Speziale, S., T. S. Duffy, and R. J. Angel (2004)
% Single-crystal elasticity of fayalite to 12 GPa, J. Geophys. Res., 109,
% B12202, doi:10.1029/2004JB003162.
%
% Pressure = 0.3 GPa
%
% Reference Crystal Structure
% Fujino, K., S. Sasaki, Y. Takeyuki, and R. Sadanaga (1981), X-ray determination
% of of electron distribution in forsterite, fayalite and tephroite,
% Acta Crystallogr., B37, 513– 518.
%
% Define density (g/cm3)
rho= 4.3991;
%
% Define Cartesian Tensor crystal symmetry & frame
cs_Tensor = crystalSymmetry('mmm',[  4.8195 10.4788  6.0873],...
 [  90.0000  90.0000  90.0000]*degree,'x||a','z||c',...
 'mineral','Fayalite');
%
% elastic Cij stiffness tensor (GPa) as matrix M
 M =.... 
 [[  273.00  104.00   97.00    0.00    0.00    0.00];...
 [   104.00  174.00   97.00    0.00    0.00    0.00];...
 [    97.00   97.00  236.00    0.00    0.00    0.00];...
 [     0.00    0.00    0.00   34.40    0.00    0.00];...
 [     0.00    0.00    0.00    0.00   48.00    0.00];...
 [     0.00    0.00    0.00    0.00    0.00   60.00]];
%
% M as stiffness tensor C with MTEX tensor command
C = tensor(M,cs_Tensor);
%
