Milky quartz is often responsible for the cloudy phantoms inside of otherwise clear rock quartz, amethyst, citrine or smoky quartz. The milky quartz may have formed at an early stage of the crystal's growth and a later stage of clear quartz growth covered the milky quartz. The effect results in seemingly a crystal within a crystal and the interior crystal may have a ghostly look, hence the name phantom. The milky quartz-amethyst phantom combination results in an ornamental stone called chevron amethyst. The bands of amethyst and milky quartz make thin well defined chevrons of purple and white that are attractive as polished stones and in ornamental carvings.
