Agate is a variety of chalcedony, a cryptocrystalline form of quartz, and is characterized by its banded structure and a wide range of colors
. It is formed within volcanic and metamorphic rocks
. Agate is essentially quartz and has similar physical properties to other quartz minerals
. The stone is found throughout the world, with notable sources in the United States, particularly in Oregon, Washington, Idaho, and Montana
. Agate is known for its translucency, patterns of color, and sometimes moss- like inclusions
. The color patterns in agates usually take the form of flat or concentric layers or bands
. Some varieties of agate include:
- Moss agate : A variety with concentric circular bands of different colors, resembling moss
- Riband agate : A variety with straight lines in cross-section, resembling ribbons
- Fire agate : A variety showing an iridescent, internal flash or "fire" caused by a layer of clear agate over a layer of hydrothermally deposited hematite
- Patuxent River stone : A red and yellow form of agate only found in Maryland
- Enhydro agate : A variety containing tiny inclusions of water, sometimes with air bubbles
Agate is often used in jewelry making due to its durability and beautiful patterns
. The stone's value is mainly based on its labor and artistry rather than the value of the material itself
. Agate can be found in various colors, including vivid, multiple colors resulting from traces of oxides of iron, manganese, titanium, chromium, nickel, and other elements
