Strength of certain soft rocks decreases about tenfold as specimen size reaches around 1 meter; at still larger sizes, it appears to remain constant. Hard rocks have not been tested over this range of sizes, so their size effect is unknown. Elastic modulus of unfractured rocks is only very slightly dependent on specimen size up to a meter. However, large fractured samples may be five to ten times more compliant than small intact samples. Friction is also size-dependent, although observations are conflicting.