  We study the formation and decay of electron-hole droplets in diamonds at
both low and high temperatures under different excitations by master equations.
The calculation reveals that at low temperature the kinetics of the system
behaves as in direct-gap semiconductors, whereas at high temperature it shows
metastability as in traditional indirect-gap semiconductors. Our results at low
temperature are consistent with the experimental findings by Nagai {\em et al.}
[Phys. Rev. B {\bf 68}, 081202 (R) (2003)]. The kinetics of the e-h system in
diamonds at high temperature under both low and high excitations is also
predicted.
