In order to determine a recrystallized grain size piezometer for quartz, we deformed Black Hills quartzite in a molten salt assembly in a Griggs apparatus at 1.5 GPa, 800 to 1100¿C, and strain rates between 2*10-7 and 2*10-4 s-1, conditions which include dislocation creep regimes 2 and 3 of Hirth and Tullis <1992>. Flow stresses ranged from 34 ¿ 16 to 268 ¿ 38 MPa with corresponding recrystallized grain sizes from 46 ¿ 15 to 3.2 ¿ 0.7 ¿m. The data are well fit by a single piezometer relation, D = 103.56¿ 0.27 * σ-1.26 ¿ 0.13, with no change in slope at the regime 2--3 transition and no effect of temperature or α/¿ stability field. Another experimental piezometer relation for regime 1 of Hirth and Tullis <1992> differs in slope, suggesting that different recrystallization mechanisms require different piezometer calibrations.