In the present study the deformation behaviour of marbles (Nacre, Yatag^ an White, Milas White) and limestones (Bursa Beige, Burdur Beige, Orient Pink) over short time periods was investigated under two loads, 19 MPa and 75% uniaxial compressive strength (sUCS) for 7 h. During the 19 MPa tests, all specimens demonstrated a regularly non-linear elasticity in secondary stage but this regularly non-linear elasticity was not observed during the 75% sUCS tests. The non-linear elasticity decreased as a function of time and ultimately ended. In the secondary stage, the ratio of the lowest strain value, el, to final strain value, ef, was defined as the stone deformability index (SDi). Building stone type and strain value were observed to be two important factors in SDi, which was found to be lower for the limestones than the marbles. The SDi decreased with increasing stone strength. The crystalline size was also observed to be an important factor in the SDi of marbles.