Agate – Brazil

Brazilian agates are one of the most famous and widely used on the world market. They come mainly from areas of southern Brazil, such as the state of Rio Grande do Sul, where they are found in the cavities of old lava flows. Over time, these cavities were filled with silica-rich quartz solutions that gave rise to the layered chalcedony. Because of the relatively large size of the cavities, Brazilian agates can grow to considerable size, often with a well-developed crystalline interior.

The most popular Brazilian agates are those with distinctive stripes in shades of grey, brown or white, often complemented by pastel tones of pink, blue or orange. A concentric pattern resembling targets or circular lines is typical, but it sometimes develops into a 'flame pattern'. During solidification, mineral solutions may have carried traces of other elements, such as iron or manganese, which cause the colour gradients.

Brazil is the world's largest producer of agates, which results in a wide market supply. This makes it one of the more affordable, especially for common pieces without specific designs. However, collectors' specimens with unusual patterns, transparent portions or crystal-filled cavities can fetch higher prices.