Amazonite in nice rough small chunks.

Amazonite, sometimes called Amazon rock, is a green variety of microclinic feldspar. The name comes from the Amazon River, from which a certain type of green stone used to be extracted, but it is doubtful whether green feldspar also occurs in the Amazon region. Amazonite is only found to a limited extent. It used to be mined almost exclusively at the Russian town of Miass in the Ilmen Mountains in the Southern Urals, where it occurs in granitic rocks. More recently, crystals were also found in Pikes Peak, Colorado, where it is contained in complexes with smoky quartz, orthoclase and albite in raw granite or pegmatite. Several other locations in the United States, including the Crystal Peak in the same Colorado, also contain amazonite layers and also in Madagascar amazonite has been found in pegmatite layers. Because of the bright green color that the mineral can get from polishing, amazonite is also sometimes chopped up and used as a gemstone, although it can easily break. People have long wondered where the green color of Amazonite comes from. Many thought that the color was due to copper, as copper deposits often have blue and green colors. However, recent studies indicate that the blue-green color is the result of small amounts of lead and water in the feldspar (Hoffmeister and Rossman, 1985).