%************************************************
% Define elastic stiffness tensor (GPa)
%************************************************
%
% Reference Elastic constants
% Isaak, D. G., O. L. Anderson, T. Goto, and I. Suzuki (1989), Elasticity of
% single-crystal forsterite measured to 1700 K, J. Geophys. Res., 94, 
% 5895–5906.
% 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= 3.221;
%
% 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','Forsterite');
%
% elastic Cij stiffness tensor (GPa) as matrix M
 M =.... 
 [[  328.00   69.00   69.00    0.00    0.00    0.00];...
 [    69.00  200.00   73.00    0.00    0.00    0.00];...
 [    69.00   73.00  235.00    0.00    0.00    0.00];...
 [     0.00    0.00    0.00   66.70    0.00    0.00];...
 [     0.00    0.00    0.00    0.00   81.30    0.00];...
 [     0.00    0.00    0.00    0.00    0.00   80.90]];
%
% M as stiffness tensor C with MTEX tensor command
C = tensor(M,cs_Tensor);
%
