In recent years, a lot of jade products from South Korea nephrite are sold on Chinese market. In order to find out the differences of the nephrites from different provenances, the authors studied the gemological and structural characteristics of South Korea nephrite for further analysis, with the purpose of distinguishing the provenances. The typical samples from South Korea were studied by using the conventional gemological methods, hardness test, polarizing microscope and scanning electron microscope test. The results shows South Korea nephrite's density is from 2.88 g/cm³ to 2.95 g/cm³, and its hardness is from 5.45 to 6.17. A comparison of the basic properties of these products from different provenances reveals evidently that South Korea nephrite's density and hardness are lower than those of other kinds of nephrite. Compared with particles of Hetian nephrite, South Korea nephrite's particles are relatively in uniform distribution. By microscopic observation, the South Korea nephrite is mainly of microaphanitic texture. The metasomatic pseudomorphic texture, metasomatic relict texture and cataclastic texture exist widely in the South Korea nephrite samples. Recrystallization is not obvious. Scanning electron microscope test reveals that the South Korea nephrite is of fibrous texture. Column-shaped and fibrous tremolite phenocrysts are abundant. Directional orientation of fibrous tremolite is very distinct.