In 2009, clusters of agate tubes were found by people living in the mountainous interior of Java, Indonesia. According to local folklore, the clumps of finger-like agate tubes form in the earth, and they think if they bury the broken fingers in the ground, they will grow and broken ends will heal. Though the shape resembles bamboo, it is not actually a bamboo fossil. Locals named it "Fossil Bamboo," after “Japanese Bamboo,” the local common name for the “scouring-rush” marsh plant genus equisetum. These wetland plants have strong silica-rich stems that were submerged in ash by multiple volcanic eruptions, and then became the nucleus for deposition of botryoidal crystallization of cryptocrystalline quartz (agate).
This agatized plant fossil comes in different colors and sizes, from single fingerlings to large clusters weighing 100 kilograms plus, with some fingers up to a foot long and 2 inches in diameter.