Oco geodes (pronounced “Oh-ko”) are small geodes found in Brazil, famous for their beautiful crystal interiors and colorful agate rims. They usually form in volcanic rock and are often just a few inches across, but what they lack in size, they make up for in sparkle. Inside, you’ll often find clear quartz or amethyst crystals, sometimes surrounded by vibrant bands of agate in earthy tones or bold hues. Because of their size and eye-catching detail, Ocos are popular in jewelry and as collectible display pieces!