Shape, Material, Color, Spirit
Although Mi Fu’s four categories are well-suited for describing Taihu Rocks, they are not comprehensive enough, and with the appearance of newer gongshi types, modern connoisseurs generally apply another set of criteria for judging rocks. These four are shape (xing), material (zhi), color (se), and spirit (shen).
Shape (xing)
The first consideration for a rock is that it should be naturally shaped. Display rocks can then be divided into two groups: abstract and representational. The former gives more room for the imagination and are admired by many people. But rock lovers also appreciate representational rocks which can be subdivided into those representing landscape and those representing particular objects. Landscape representational rocks resemble hills, scenes after snow, cliffs and peaks. They can be further subdivided into those representing near or far distant scenes. The latter should exhibit proportion between height and width to give a proper framework for the vista represented. Rocks resembling particular objects, such as human figures and animals may either bear such likeness in shape or spirit. The merit of the latter is that they both resemble and yet do not resemble a given object.
Material (zhi)
Display rocks should be hard in material and rich in texture. If shape pertains to the outward appearance of rocks, material refers to their inward quality. If the rock material is of good quality, even though it may have a less intriguing shape, it may still have value for a collector. Yet a rock that exhibits material hardness may also be concise in texture and upright or firm in appearance — qualities that will make it unique for display. In addition, the sound quality of a rock is closely linked to the quality of the material.
Color (se)
Ideally, the hue and the luster should be natural, simple and pure. Most display rocks are naturally black, gray or yellowish brown, and hence are not valued for their bright coloration. Some old rocks that have been exposed to air or frequently touched by human hands have a special coating on the surface called baojing, a hue of natural antiquity that enhances the value of such rocks.
Spirit (shen)
Some rocks seem animated and inspiring; others manifest artistic conception — an insight or revelation that provokes thought and captivates the viewer. These qualities are quite subjective, and while collectors in the West may pay attention to more objective criteria such as shape, material, and color, their romantic charm and artistic conception are also features that make them unique for contemplation and appreciation. It is said that “a rock, though small, will show its intelligence when it has spirit”. Display rocks may appear to be in an active state or one of inertia. Rocks with inertia convey serenity and calmness as well as a sense of strength, while the more animated seem to fly, dance, shout or jump. Amidst life’s commotion and distractions, it is for the rock lover to catch that moment. he great Song literati Mi Fu formed an appreciation of rocks based on his own aesthetics as well as what he knew of past collections. The four categories he considered essential to the appreciation of rocks were shou, zhou, lou, and tou. These four criteria are still used by connoisseurs today, especially for Taihu rocks.