Many natural and synthetic crystals contain entrapped fluids representative of their growth medium. The following method was developed for the chemical analysis of such fluids:1. Hand-cobbing, heavy media separation, and electrolytic cleaning to remove adsorbed surface ions.2. Release of inclusion ions by ball-milling.3. Separation of the inclusion ions from the ground mineral by electro-dialysis.4. Chemical analysis of the collected inclusion ions. Inclusion analyses of a suite of New Mexico minerals showed the major cations to be sodium and potassium with lesser amounts of lithium, rubidium, and cesium, and the major anions to be chloride and sulfate in an aqueous solution. A quantative determination of the above ions was made.In the minerals from Portales, New Mexico, a correlation appears to exist between the sodium to potassium ratio and the temperature and sequence of deposition. Falling temperature is paralleled by a decreasing sodium to potassium ratio. This indicates an uninterrupted supply of mineral depositing solution over an extended time period.Similar sodium to potassium ratios were found in two fluorite samples from similar geological environments.