Introduction

Amazonite is a green variety of microcline feldspar and is also known as the "Amazon stone".

It is not clear where the name of this mineral comes from. Although there is no news of green feldspar deposits in the Amazonian plain, some sources trace the name back to the Amazon River where these green stones were found. Their presence in the river bed is therefore due to river transport starting from the mountain deposits where this mineral is present.

Other sources trace the name Amazonite to the Amazons, the mythical warrior women who, according to legends, loved this mineral and adorned it for its green color.

The Amazonite can have both a magmatic origin, in particular it is formed in the hydrothermal or pegmatitic phase of the magmatic process, both a sedimentary origin and a metamorphic origin.

Curiosity

In the past, many names have been attributed to this mineral. Only from the eighteenth century it was given the name by which it is known and called today.

Among the many names given to the Amazonite there is "stone of hope" as in ancient times it was believed that its beautiful green color gave hope to those who observed it.

Amazonite was also known as “Amazonian rock”, this probably because of its similarity to another mineral, nephrite, which, according to the Indians of the Rio Negro, came from the “Land of women”. For this reason, Amazonite was attributed the property of making women who wore it beautiful and attractive.

Already at the time of the ancient Egyptians the stone was known, although it is not known what name it was called, and it was used for the creation of wonderful artifacts.

It is considered a birthstone for gamblers because it promotes self-control.

Polished Amazonite

Why is it green?

For a long time the origin of the green color of the Amazonite was not clear. Initially it was believed that the green color was given by the presence of copper within the crystal lattice of the mineral. In fact, it is known that the presence of copper tends to give the minerals blue or green tones. More recent studies, on the other hand, attribute the green color to the presence of small quantities of lead and water in the crystal lattice of the mineral.

Where is it?

Amazonite is not a very common mineral. The largest Amazonite deposits are found in Russia, where it is quarried within granite rocks. As for the high quality crystals, these are mostly extracted in the United States, more precisely in Colorado, where this mineral is often found in association with quartz, orthoclase and albite crystals within granites or pegmatites. Other Amazonite deposits are present in Madagascar and Brazil.

Property

  • Mineral Class: Silicates (tectosilicates)
  • Crystalline group: Trimetric
  • Crystalline system: Tricline
  • Chemical formula: KAlSi3O8
  • Hardness (Mohrs): 6
  • Density: 2.53-2.56 g / cm³


Polished Amazonite

Uses

Thanks to its green color, Amazonite is suitable for use in jewelry as a semiprecious stone. Starting from the raw mineral it is processed so as to be transformed into a gem. As a gem it is used for the creation of rings, brooches and pendants, spheres for natural stone necklaces and bracelets. It is also used for the creation of artistic crafts.


Bibliography

Hoffmeister and Rossman, A spectroscopic study of irradiation coloring of amazzonite; structurally hydrous, Pb-bearing feldspar, in Am. Min., vol. 70, 1985, pp. 794–804.

Font-Altaba and A. Macrì, Tables of Mineralogy (1967) CEGiunti Bemporad Marzocco

Rupert Hocleintner, Guide to Minerals (2017) Rich editor