Below the measured Q values of the six Suprasil 313 substrates, with polished edges, after annealing at 900 degrees C for 9 hours.

They are all consistently at a level of 100e6 at 1 KHz and showing a similar frequency dependency going down to a about 30e6 at 20-30 kHz. The only exception is S1600522 which has clearly lower Q values at all frequencies.

Below a comparison of the substrate loss angles compared wiht Steve Penn's model: