Many physical properties of rocks depend strongly on pore volume fraction and pore geometry. Petrgraphic studies indicate changes in pore geometry caused by healing and sealing of cracks are ubiquitous in igneous, metamorphic, and even sedimentary rocks, and recent laboratory experiments have shown that crack healing is extensive at relatively low temperatures in minerals with aqueous pore fluids. Theories for the evolution of the shapeof a solid acted on by capillarity forces have been successful in predicting several aspects of crack healing experiments done in cracked single crystals of olivine, quartz, calcite, and halite. The PI will continue to investigate the influence of temperature, pressure, non.hydrostatic loading, and crack shape on crack healing in quartz, halite, and calcite with aqueous fluids and to do experiments on the effect of crack healing on permeability.