石筍, or "stone pillars," are natural rock formations that resemble stalagmites. They are typically found in caves and are formed by the deposition of minerals from dripping water over long periods. As water seeps through the ground, it carries dissolved minerals, which accumulate and solidify, creating these unique structures. These formations are often composed of calcium carbonate, similar to 鐘乳石 (stalactites), which hang from cave ceilings. 石筍 can vary in size and shape, contributing to the stunning beauty of cave systems. They are popular attractions in many natural parks and are studied for their geological significance.