Deep blue color, blue streak, and common association with green Malachite. As a secondary mineral in the oxidation zone of copper deposits. Rock Type. Sedimentary , Metamorphic. Popularity Prevalence Demand Azure Copper Ore.
Azure-Malachite - Mixture of blue Azurite and green Malachite. Azurite is very popular mineral among collectors. Bright blue pieces are polished into cabochon s and beads, and large masses are sometimes cut into ornamental objects. Azurite was formerly crushed and used as a blue pigment. Azurite is also an ore of copper. Fine Azurite specimens have been obtained from numerous places.
Some of the largest and best individual crystals have come from Tsumeb, Namibia. Morocco has also produced excellent crystals at Touissit and Kerrouchene. In the U. Azurite also occurs in the Rose Mine in Grant Co. Linarite - Softer, heavier, doesn't effervesce in hydrochloric acid. Lirconite - Lighter and more greenish in color, softer. Connelite - Different crystal habits, doesn't effervesce in hydrochloric acid.
Cyanotrichite - Lighter in color. Cornetite - More greenish in color, doesn't effervesce in hydrochloric acid. Slab is about 8 centimeters long. Photographed wet to show full color. From near Bisbee, Arizona. Azurite is a secondary mineral that usually forms when carbon-dioxide-laden waters descend into the Earth and react with subsurface copper ores. The carbonic acid of these waters dissolves small amounts of copper from the ore.
The dissolved copper is transported with the water until it reaches a new geochemical environment. This new environment could be a location where water chemistry or temperature changes, or where evaporation occurs.
If conditions are right, the mineral azurite might form. If these conditions persist for a long time, a significant accumulation of azurite might develop. This has occurred in many parts of the world. Azurite precipitation occurs in pore spaces, fractures, and cavities of the subsurface rock.
The resulting azurite is usually massive or nodular. In rare situations, azurite is found as stalactitic and botryoidal growths. Well-formed monoclinic crystals are infrequently found. These can only occur if azurite precipitates unrestricted in a fracture or cavity and is not disrupted by later crystallization or rock movements.
Malachite is another copper carbonate mineral that forms under conditions similar to azurite. These minerals are often found in the same deposit and are often intergrown with one another. This produces a material known as azurmalachite , which, when of high quality, can be used as a beautiful lapidary material. More important deposits have been found in France and Namibia. Azurite Nodules in Sandstone: Small azurite nodules about one centimeter in size in a matrix of fine-grained sandstone.
From the Nacimiento Mine, New Mexico. The most diagnostic property of azurite is it distinctive deep blue color. It is also soft with a Mohs hardness of only 3. It contains copper, which gives its blue color and a specific gravity of 3. Azurite is a carbonate mineral and produces a slight effervescence with dilute hydrochloric acid , producing a light blue liquid.
Azurite produces a light blue streak on unglazed porcelain. While azurite is not an extremely abundant mineral and is rarely found in large deposits, it has been used in a number of ways.
Some of these are explained below. Azurite "Blueberries": Small nodules of azurite, between five and ten millimeters across, that weathered out of a poorly-cemented sandstone near La Sal, Utah. Geologists know that abundant azurite is often found in the rocks above deposits of copper ore.
That enables them to use azurite as an indicator mineral in the search for subsurface copper deposits. The presence of abundant azurite indicates the possibility of finding some form of copper ore below, nearby, or up a contemporary or ancient hydraulic gradient. Azurite has been used as an ore of copper metal for thousands of years.
The ancient Egyptians mined it on the Sinai Peninsula and smelted it to produce copper. Today, azurite deposits on their own are usually not large enough to be worth opening a copper mine. Where other copper ores are mined, azurite might be removed if it is of adequate grade and easy to mine. Azurmalachite Cabochons: Azurite is frequently associated with malachite, and that association can produce very interesting gem materials. These cabochons were cut from a material known as "azurmalachite" produced at the Morenci Mine in Arizona.
They were cut from thin vein material and have a natural wall-rock backing. Both cabs are about 25 millimeters tall. It performs well as a lapidary material and gemstone. Photographed dry. This piece is about ten centimeters across, and the largest orb is about on centimeters across. The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties.
The crystals have complex tabular habit, a deep blue color, and, occasionally, thin coatings of malachite. The azurite occurs with tenorite and limonite as alteration products of chalcopyrite. Some specific localities from the Mineral Point area given by Heyl et al. At the Ansley Mine, the copper minerals occur as masses weighing up to lb in clay. Some crystal cluster form rosettes up to 2 cm.
Cordua, field notes. Question about Wisconsin geology?
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