GPa

GPa stands for gigapascal, a unit of pressure or stress in the International System of Units (SI). It equals one billion pascals (1 GPa = 10^9 Pa). Because the pascal is a relatively small unit, gigapascals are commonly used to express stresses and elastic properties of solids, such as Young’s modulus, yield strength, and fracture strength. In practical terms, 1 GPa equals 1000 MPa (since 1 MPa = 10^6 Pa).

For reference, 1 GPa is about 145,038 psi, and 1 GPa is 0.001 of a terapascal (1 TPa = 10^12 Pa). In geology and geophysics, pressures within rocks and Earth's crust are typically reported in MPa to GPa ranges. In engineering and materials science, GPa is the standard scale for stiffness and strength measurements.

Common material values illustrate the range: metals such as steel have a Young’s modulus around 200 GPa; many ceramics lie in the 100–500 GPa range; diamond has a modulus around 1000 GPa (approximately 1 TPa). Polymers and composites exhibit wide variations, often lower than metals. In high-pressure physics, equipment like the diamond anvil cell can generate pressures above 100 GPa, and experiments have reached several hundred GPa in specialized setups.

In summary, the gigapascal is the widely used unit for large pressures and for describing mechanical properties of materials, bridging everyday engineering contexts and high-pressure research.