Soft and lightweight volcanic or sedimentary stones have traditionally not been used, although in recent years they have gained in popularity outside Japan. Having selected a stone of appropriate size and hardness, the collector is primarily concerned with the stone's aesthetic qualities. Suiseki arc often given fanciful names that express the suggestive qualities of the stone. Paradoxically, it is often the case that the simpler the stone, the greater its richness and expressive possibilities. By presenting only a suggestion of the object, by expressing more with less, Such stones stimulate and challenge the imagination, inviting the viewer to complete the picture.
Color is a vital element in the suggestive power of suiseki.
The most prized suiseki are those that possess a blend of subtle colors arising from deep within the stone, as if illuminated by a hidden light source. Balance provides much of the aesthetic interest of a suiseki. In a well-formed suiseki, asymmetrical elements combine together to create an integrated, stable and harmonious whole. Suggestiveness, subdued color and balance are all important qualities of all classical suiseki. Although each word conveys a vaguely similar meaning and feeling, each differs in nuance and connotation.