Colorado amethyst.

Of the 20 or so amethyst localities reported in Colorado, four are described in some detail and comments are given on their geology. The Crystal Hill mine, near La Garita, Saguache County, contains rock crystal (long slender prisms with small rhombohedral terminations) and pale lavender amethyst (generally <3 in. in length). The deposit was worked as early as the 1800's as a gold mine and also contains abundant manganese oxides. Amethyst, associated with argentiferous galena, sphalerite and chalcopyrite, occurs in the Amethyst mine, in the Creede district, on West Willow Creek, Mineral County. The specimens here consist of small pale pinkish-purple crystals interlayered with milky quartz, some as banded forms ("sowbelly agate') and as geode-like vugs. Amethyst also occurs in Unaweep Canyon south of Grand Junction in Mesa County. Pale to very dark amethyst occurs as crystals dominated by large rhombohedra and small prisms (approx 1 in. across). At Red Feather Lakes, Larimer County, amethyst crystals are medium to dark purple and have prism and rhombohedral faces nearly equally developed; some are doubly terminated. -R.S.M.