The elastic constants, thermal expansion, thermal conductivity, and heat capacity are reported for a new class of laser hosts‐the silicate oxyapatites. For Ca2La8(SiO4)6O2the five independent elastic constants obtained from sound velocity measurements areC11=1.71,C12=0.62,C33=1.71,C44=0.52, andC13=0.39×1012dyn/cm2, the thermal expansion coefficients at 300 K are 8.9×10−6and 6.6×10−6K−1for the [101¯0] and [0001] directions, respectively, and the room‐temperature conductivity is about 0.019 W cm−1K−1. Sound velocity and thermal expansion data suggest a Debye temperature between 400 and 500 K.