Tumbled Banded Mixed Amethyst / 20-50mm AVG - 1 KILO LOT Menu Specimen with Cut Base Amazonite is a potassium-based feldspar

Amazonite is a potassium-based feldspar

the latter taking its color from very small inclusions of fluid or gas while it formed

The natural aragonite in these fossils instead forms a nacre-like sheen

Amethyst Tree with Crystal Base / Medium

Tumbled Banded Mixed Amethyst / 20-50mm AVG - 1 KILO LOT Menu Specimen with Cut Base Amazonite is a potassium-based feldsparQuantity: 1 kilogram Average size range: 20 to 50 millimeters Amethyst is a violet gemstone that occurs when quartz containing significant iron impurities and other trace elements undergoes natural geological irradiation over long periods of time, altering the color. Chevron amethyst, also known as banded amethyst, contains white quartz in addition to amethyst, which forms this distinctive banding pattern.