Amazonite

Hardness: 6-6.5 on Mohs scale. Color: Green to blue-green, sometimes variegated with white streaks. Luster: Vitreous to sub-vitreous. Crystal Structure: Triclinic; typically forms short prismatic crystals, but also massive. Cleavage: Good in two directions at nearly right angles. Specific Gravity: 2.56-2.58.

Amazonite is a tectosilicate mineral that forms in granitic pegmatites, often found with other minerals like quartz, albite, and mica. It also occurs in some metamorphic rocks and hydrothermal veins. Its characteristic blue-green color is believed to be due to traces of lead and water within its crystal lattice, rather than copper as previously thought. Geological age varies depending on the host rock formation, but it is found in many ancient and relatively younger intrusive igneous rocks.

Primarily used as a gemstone and ornamental stone. It is often cut into cabochons, beads (as seen in the image), and polished into decorative objects. Due to its attractive color and moderate hardness, it is popular in jewelry. It has no significant industrial uses beyond its aesthetic appeal.

Amazonite is a variety of microcline, which is a potassium feldspar mineral. Despite its name, it is not found in the Amazon River region in significant quantities. The name was given due to some green stones found there initially, which were mistakenly identified as amazonite. Notable deposits are found in Russia's Ilmen Mountains, Colorado (USA), Brazil, and Madagascar. It is also known as the 'Amazon Stone'.

In the field, amazonite is identified by its distinctive blue-green color, which can range from pale to vivid. Its moderate hardness (scratching glass but not quartz) and vitreous luster are also key. It often shows white streaks or patches of albite. It is commonly found in pegmatite veins traversing granite or gneiss. Collectors look for well-formed crystals and intensely colored specimens. Care should be taken as some dyed chalcedony or synthetic materials can mimic its appearance, but a scratch test or specific gravity measurement can help differentiate.