It is a kind of powdery high molecular protein with a molecular of 100,000, which is no taste, no smell, and is micro-dissolved in water, but not in ethanol. For making the silk cosmetics, the fineness of silk powder is generally between 1-100?if the grain size is too big, the smoothness of silk powder shall be poor,and give people the feeling of crude, but it would spoil the structure of natural silk material if the grain size is too fine. Since the surface gloss of silk is caused by the light interference effect on the silk surface, the fineness should be treated properly during the production process for silk powder, so as to keep the best standards of fineness, as well as the unique natural luster of it.