Improved contaminant removal from alkaline- or alkali-earth metal fluoride crystal growth material can be obtained by coprecipitating an alkaline- or alkali-earth metal fluoride with a scavenging agent during synthesis of the fluoride growth material. The coprecipitation of the alkaline- or alkali-earth metal fluoride and scavenging agent can be performed using at least one of chloride, nitrate, hydroxide and carbonate salts of the alkaline- or alkali-earth metal fluoride and scavenging agent. This provides a more intimate mixture or dispersion of the scavenging agent in solid solution or as a mechanical mixture with the alkaline- or alkali-earth metal fluoride for improved outgassing and fewer trapped impurities, leading to improved radiation hardness and bulk absorption.