type: Hooke

references:
  - H.M. Ledbetter,
    physica status solidi (a) 85(1):89-96, 1984,
    https://doi.org/10.1002/pssa.2210850111

C_11: 204.6e+9
C_12: 137.7e+9
C_44: 126.2e+9