Diamonds in the rough, note the regular octahedral forms and trigons (of positive and negative relief) formed by natural chemical etching. Photo credit: Wikimedia.


A gemstone is any rock or mineral that may be used for ornamentation or jewelry. Gemstones usually are minerals prized for their color, beauty, rarity, and endurance. Typically, they are cut and polished to bring out their natural beauty. Even diamonds must be cut into faceted shapes to really sparkle. Colorado has more than thirty varieties of gemstones including aquamarine, rhodochrosite, amazonite, topaz, and diamonds. The official state gemstone is aquamarine, a beautiful blue mineral mostly found around the 13,000-foot (4,000 m) level on Mount Antero. Gemstone quality rhodochrosite, the state mineral, is produced from the Sweet Home Mine located in Alma mining district, Park County. The largest faceted diamond sourced in the United States (16.87 carats) was found in Colorado. Other notable gem-quality minerals that have been found in Colorado include garnet, tourmaline, lapis lazuli, quartz crystal, smokey and rose quartz, amethyst, turquoise, peridot, sapphire, and zircon. Agate, chalcedony, and jasper, three varieties of cryptocrystalline quartz, are also found in many places.