Absolute pressure measurements and analysis of diamonds subjected to maximum static pressures of 1.3-1.7 Mbar.

Force per unit area measurements made in the megabar pressure cell, independently of other pressure calibration systems, are consistent with the ruby R1 scale of Mao, Bell, Shaner, and Steinberg and its extrapolation to 1.4 Mbar. Physical analysis of diamond anvils removed after experiments to maximum pressures of 1.3-1.7 Mbar suggests that the nitrogen platelet concentration may be related to the strength of the diamonds. The pressure face of one of the diamonds from the 1.7-Mbar experiment was deformed plastically by a macroscopic amount.