China is the most ancient area of jade culture in the world. With the rise of jadeology, the phase composition of jade and its mechanism of etching have become a concern to the community. In our study, we used scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX), laser Raman microspectrometry (LRS) and Fourier transform infrared spectrometry (FTIR) to analyze four jade fragments from Tomb M88 from the Sujialong Site in Jingshan, Hubei Province as well as one modern Hotan jade sample. In addition to the fibrous mineral components, tremolite jade also contains higher fatty acid salts which exist in a glass phase. The fatty acid salts are distributed as a buffer in the grain boundary and gaps, so that the tremolite has high flexibility and does not break easily. During the etching, fatty acid salts were dissolved out and some were enriched at cracks and loose areas, adsorbing other substances to cause jade to be etched. After the loss of a large amount of fatty acid salts, the internal chains of tremolite are prone to breaking. In this process, the Ca-O and Fe-O bonds in the chain are broken before breakage of the Mg-O bond due to their lower strengths. The actinolite structure is reduced accordingly and the translucent jade turns opaque and is even whitened.