Published online by Cambridge University Press: 04 March 2005
We present results on the room temperature mechanical quality factor of single crystal calcium fluoride (CaF2) grown by the Bridgman-Stockbarger method. Resonant mode Q-factors are measured in the frequency range 20 to 76 kHz using tungsten wire loop suspensions. In spite of indications of only moderate crystal purity, we observed 6 modes with Q-factor > 107, and one with $Q = 4.5 \times10^{7}$ , more than an order of magnitude higher than previously reported results.