Conventional gemological and spectroscopic analyses are conducted to reveal the gemological and mineralogical affiliation of the speciality of Xiuyan jade, Jiacui. The conventional gemological analysis revealed that Jiacui is a light green and white mottled nephrite with a waxy or oily luster, opaque to slightly transparent. The refractive index of 1.56 and the density in the range of 2.53 to 2.67 g/cm³ are measured. Microscopic observation, infrared spectroscopy, and Raman spectroscopy revealed that the Jiacui is composed primarily of antigorite, with secondary minerals such as tremolite, calcite, and dolomite, of which tremolite is relatively common. Raman spectroscopy combined with electron microprobe analysis shows that the green part of the Jiacui is usually antigorite, while the white spots are either tremolite or carbonate minerals such as dolomite and calcite. Considering that carbonate minerals are not suitable to participate in jade nomenclature as long as they are attached in the form of peridotite, it is suggested to limit Jiacui jade to a kind of serpentinized jade containing tremolite.