The word suiseki is derived from the Japanese kanji for water - sui - and stone - seki - translating literally as "water-stone" - a stone shaped by the erosive action of water.
Suiseki is the companion artform of bonsai, and like bonsai, the word refers to both the art itself & the objects of the art. The purpose of suiseki is the study of & pleasure taken from individual, naturally formed stones.
It originated in China almost two thousand years ago & was adopted by Japan in the trade between the two countries that flourished in the Middle Ages. As with other imports from her neighbours, Japan not only adopted but adapted suiseki to her own culture, turning it into what is now regarded as a thoroughly Japanese art.
To the uninformed, suiseki can appear to be little more than pretty rocks set on wooden base, and it's important to note what separates a suiseki from an "interesting stone".
Firstly, it should have a shape that the viewer finds pleasing.
Second, the stone needs to be clean & tastefully displayed. They're normally displayed in either a shallow container - a suiban - or on a wooden stand - a daiza - both tailored to enhance the visual effect of the suiseki.
Finally, the stone should stir the emotions. Its shape should conjure an image of a place or natural object in the viewer's mind.
If it fulfills all three of these requirements, then it is a suiseki.
Suiseki are classified according to their shape. For example, Object Stones are stones that resemble the natural shapes of animals or people, whereas Scenic Landscape Stones are suiseki that appear to depict landscape features like mountain ranges.