Taihu Rocks are found mostly in the vast drainage areas of Tai Lake, these limestone rocks are hard but brittle, with slight variations among those taken from lake beds and those extracted on land or from different districts in the surrounding environs. Those formed underwater are more precious, because of their fresh, soft color and their multiple, linked perforations produced from years of wave and water erosion. With their pale gray or ivory tint, Taihu rocks are usually large and are regarded as the best garden rocks. Artificial hills made of Taihu rocks give the appearance of strang peaks looming up or chains of hills connected by streams and bridges, with successive peaks along narrow, twisting paths. Small Taihu rocks of good quality are rare and meant for indoor appreciation. The beauty of Taihu rocks comes from their thinness and wrinkles as well as their perforations and hollows which enhance their open appearance.