Dioptase is known as the gem of the Congo. Other names for it include copper emerald and achrite. It is also sometimes known as the emerald of the poor because it looks like emerald but is much more fragile. Dioptase was named in 1797 by mineralogist R. J. Hauy. The name comes from the Greek word dia for through, and optomao, to see, a reference to the visibility of the stone's internal cleavage planes. Dioptase is a hydrated copper silicate that is highly valued by mineral collectors. Dioptase crystals usually take the form of short, six-sided prisms, often terminated by rhombohedra. It occurs in massive form and has sometimes been found in the oxidized, weathered parts of copper sulfide deposits with copper minerals such as chrysocolla. It is also found in association with dolomite, calcite, cerussite, and limonite.
Dioptase is of a gorgeous vivid emerald green color, with a hint of blue. Collectors prize the stone for its color and it has sometimes been confused with emerald. It has extremely high fire, however the fire is masked by its strong color, which makes the stones appear translucent, rather than transparent. Dioptase is rarely faceted as stones are brittle and fragile, rating only a 5 on the hardness scale; the stones are too soft to be worn on a regular basis. When dioptase is cut, it is usually cut into cabochon or brilliant cuts. When it is faceted, only the clear ends of large crystals are used for faceting. Cut dioptase stones often have a pearly appearance caused by the reflection from its tiny internal cleavage cracks.
The best quality dioptase comes from Russia, Namibia, Chile, Zaire, and in the United States, in Pinal County, Arizona. Major deposits also exist on Mount AltynTyube, Kazakhstan. In Africa, large specimen is found in Otavi, Namibia and the Pool region of the Republic of Congo. Other sources of dioptase include the Shaba province of the Democratic Republic of Congo as well as Chile and Argentina.
There are many beliefs in the mystical powers dioptase possesses. It is a stone that has a happy, playful energy and has been called a heart healer. This playful energy is able to heal one's inner child, releasing repressed pain that one might carry around for years. It also fills an emotional black hole that might be desperate for love, and it brings one closer to the inner self. Physically, it has been said to help regenerate the liver.