Abstract: The concept of the ornamental stone is explored in the paper. According to its geological background, morphological characteristics and special significance, the ornamental stone is classified into five categories:modeling stone, pattern stone, crystal, fossil and special stone. The impact on the value of the ornamental stone is analysed from the following factors, such as types, quality grade, rarity, origin, combination, special significance and market changes. Finally, the appraisal methods on the value of the ornamental stone are discussed and the present major problems faced when appraising the stone are also analysed.