Gongshi
Gongshi (), also known as scholar's rocks, are naturally occurring or shaped rocks which are traditionally appreciated by Chinese scholars. Scholars' rocks can be any color, and contrasting colors are not uncommon. The size of the stone can also be quite varied: scholars' rocks can weigh hundreds of pounds or less than one pound. The term also identifies stones which are placed in traditional Chinese gardens. History. In the Tang dynasty, a set of four important qualities for the rocks were recognized. They are: thinness (瘦 shòu), openness (透 tòu), perforations (漏 lòu), and wrinkling (皺 zhòu). Gongshi influenced  the development of Korean "suseok" and Japanese "suiseki". Sources. There are three main Chinese sources for these stones. The geological conditions needed for the formation of stones are also present at some other sites. Formation. Scholar's stones are generally karstic limestone. Limestone is water-soluble under some conditions. Dissolution pitting dissolves hollows in the limestone. On a larger scale, this causes speleogenesis (when caves dissolve in limestone bedrock). On a still larger scale, the dissolved caves collapse, gradually creating karst topography, such as the famous landscapes of Guilin in the South China Karst. As rocks are broadly fractal (geology  journals require a scale to be included in images of rocks), the small rocks can resemble the larger landscape. Aesthetics. The aesthetics of a scholar's rock is based on subtleties of color, shape, markings, surface, and sound. Prized qualities include: The stone may be displayed on a rosewood pedestal that has been carved specifically for the stone. The stones are a traditional subject of Chinese paintings.