Indentation elastic moduli of Q-carbon, diamond, and sapphire. (a) MoNI indentation curves measured on Q-carbon filaments (blue line), CVD diamond film grown on silicon (violet line), and on a sapphire substrate (cyan line). (b) Indentation moduli (in GPa) for Q-carbon (blue markers), CVD diamond (violet markers), and sapphire (cyan markers). The moduli are obtained by fitting the curves in (a) with the Hertz model[11,12] using the procedure detailed in the “Methods” section. The box plots show the median of the measurements (solid black line) as well as the 25th and 75th percentiles (top and bottom limits of the box).