Amazonite is a trading name for the green or blue colored gemstone, microcline. Microcline is a form of orthoclase feldspar, and feldspar makes up most of the earth’s crust. Feldspar is found all over the world in all types of rock formation, igneous, metamorphic, and sedimentary. Feldspar is made up of silica and aluminum and forms in a number of ways, for example during crystallization of magma or lava, being subject to high temperatures and great pressure below the earth’s surface or crushed in sedimentary rock.
For many years, the source of amazonite's color was a mystery. Some people assumed the color was due to copper because copper compounds often have blue and green colors. Other studies suggest the colors are associated with the increasing content of lead, rubidium, and thallium. A recent study also implicated the role of divalent iron as the reason behind its lovely green hue. These studies and associated hypotheses indicate the complex nature of the color in amazonite, in other words, the aggregate effect of several mutually inclusive and necessary factors.
Amazonite is technically translucent but to all intents and purposes, it is an opaque gemstone with just a few examples being clear enough for very much light to shine through.
When polished, Amazonite has a waxy and glassy shine so it is not surprising that it was used alongside turquoise and lapis lazuli to make beads, amulets, scarabs in Ancient Egypt. It was also used to decorate and enhance bracelets, armbands, and collar pieces as inlaid flourishes on royal jewelry.
The gem was first named “Amazon stone”, after the Amazon River, although there are no known occurrences near that river. That name evolved into Amazonite, which sounds more appropriate for a gem or a mineral.
Amazonite has been used as a gem for over 2000 years. It has been found in archaeological excavations of ancient Egypt and Mesopotamia (an area that covered portions of present-day Iraq, Kuwait, Syria, and Turkey). This gemstone, under different names, has been in use since at least the time of the Pharaohs of Ancient Egypt. In an archaeological dig undertaken in southern Jordan more than 2000 fragments of amazonite jewelry were discovered dating back to neolithic times, perhaps 10,000 years ago!
Amazonite is now known to occur in various places around the globe. These days amazonite is mostly to be found in China and Mongolia in East Asia, in the Ural Mountains of Russia, southern and eastern Africa, Brazil (though not in the Amazon region!), and in Colorado and Virginia in the United States.
The USA has exceptionally fine deep blue and green deposits in Pikes Peak, Devils Head, Lake George, and Florissant in Colorado. All amazonite mined from this area is called "Pikes Peak Amazonite", as all the material from this area is almost identical. Deep green amazonite has been found in the Kola Peninsula, Russia, and the famous mines of Minas Gerais, Brazil as well as Mogok in Burma or Myanmar and Sidamo-Borana Province in Ethiopia.