Embodiments include an apparatus and method for testing a particulate material suitable for use as a proppant. According to one embodiment, a sample of the particulate material is captured in the cavity of a test vessel between a cavity wall and a piston sealed with the cavity wall. A fluid is flowed into the test vessel from a fluid inlet of the test vessel to wet the sample of particulate material. The fluid is pressurized to a target fluid pressure greater than ambient pressure and heated to a target temperature greater than ambient temperature. The piston is moved into direct contact with the particulate material with sufficient force to crush at least a portion of the particulate material while maintaining one or both of the target temperature and the target pressure for one or more test cycles. Each test cycle has a duration of at least about 120 seconds and as long as about 24 hours.