The previously determined optical properties of SrB4O7;Sm2+make this compound a possible better pressure calibrant than ruby, particularly when used at elevated temperatures. Moreover, it can be used with the same experimental devices. In fact, SrB4O7;Sm2+displays an intense emission line which is a nondegenerated singlet,5D0−7F0, at 685.41 nm in the same spectral range as ruby, 694.22 nm. In the present study, its shift with pressure has been calibrated with the shift of the ruby R1line up to 60 GPa and has also been recorded to over 100 GPa. No phase transition of SrB4O7;Sm2+was found at least up to 108 GPa. The pressure profiles in the diamond anvil cell have been established at 60 and 105 GPa. In addition, the bulk modulus of SrB4O7;Sm2+, B0=170 GPa, has been determined from x‐ray diffraction experiments up to 27 GPa. An analytical expression for the shift of the wavelength with pressure is derived and applications to ruby and strontium borate are given.