gems, treatments, heat treatment, inclusions, quartz, citrine, amethyst, goethite, hematite

Important article that details how goethite inclusions, are altered to hematite by heat treatment of amethyst to citrine. This note describes the conversion of goethite to hematite when amethyst containing goethite inclusions is heated to produce brownish yellow coloured “fired” citrine quartz. The resulting hematite pseudomorphs after goethite are always accompanied by at least some fracturing in the amethyst-citrine because of water loss during dehydration of the inclusions.