argon gas, 300 K | 1.1584e-12 | 1.1584e-12 | matter | stiffness per particle 0.0431 eV; rest energy 37.2 GeV; v = 322.7 m/s (here the 'stiffness' is gamma kT, thermal)
helium gas, 300 K | 1.1567e-11 | 1.1567e-11 | matter | stiffness per particle 0.0431 eV; rest energy 3.73 GeV; v = 1020 m/s 
liquid argon, 87 K | 7.8583e-12 | 7.8583e-12 | matter | stiffness per particle 0.292 eV; rest energy 37.2 GeV; v = 840.4 m/s 
rock salt, [100] lengthwise | 2.5252e-10 | 2.5252e-10 | matter | stiffness per particle 6.87 eV; rest energy 27.2 GeV; v = 4764 m/s (per ion)
liquid sodium, 373 K | 7.1276e-11 | 7.1276e-11 | matter | stiffness per particle 1.53 eV; rest energy 21.4 GeV; v = 2531 m/s 
Aspden's lattice, shear (cube diagonal) | 4.6096e-02 | 4.6096e-02 | aspden | stiffness per particle 961 eV; rest energy 2.08e-05 GeV; v = 6.437e+07 m/s (Coulomb shear, Part 1 U38)
Aspden's lattice + orbit gyrostats (V-S) | 2.0340e-01 | 2.0340e-01 | aspden | stiffness per particle 4.24e+03 eV; rest energy 2.08e-05 GeV; v = 1.352e+08 m/s 
light | 1.0000e+00 | 1.0000e+00 | light | would need stiffness per particle = rest energy
