Amazonite JewelryWhere the name comes from: The Amazon River, though no stones have been found in the region, it may be a reference to the green coloration.
Where the stones come from: Infrequent localized occurrences, Colorado, Russia, Brazil, Madagascar.
Chemistry: Potassium aluminium silicate, KAlSi3O8 - a green variety of feldspar,
Colors: Green to blue-green to yellow-green, the color comes from the inclusion of lead, water and possibly iron.
...and another thing: Heating above 300C will lose the color.