Residual strains in single crystals of quartz and orthoclase from the discordant intrusive at the Tin Mountain Mine, Custer County, South Dakota are consistent within each crystal but vary widely from one crystal to another. Residual strains in a plagioclase crystal are related to crystal geometry and to exsolution features. Residual strains in and about a tabular concordant pegmatite mass at the Skyrocket Mine are related to the geometry of the body. These facts are thought to indicate that a "fabric" of small residual stress domains exists within each mass of material examined. Similarity, but not exact reproducibility, of results is explained by variations of stress from one domain to another.--Modified journal abstract.