The bottom refers to the extent of jade flocs (also known as cotton ), dark spots, and other stains. Because jadeite is a collection of various minerals, its structure is mostly fibrous structure and granular structure, and the degree of impurities will inevitably affect the value of jadeite. Level division standard 1 grade 10 times magnifying glass does not see any splitting, grayish black silk, occasionally individual white cotton, small black spots in the inconspicuous place 2 grade 10 times magnifying glass, no cracks, see a small amount of fine white cotton, black spots, gray black silk Grade 3 has no cleft palate, a small amount of cleft palate under a magnifying glass of 10 times, a small amount of white cotton, black spots and a small amount of ice residue visible to the naked eye. 4th grade, see a small amount of cleft palate and more white cotton, black spots, gray silk and ice residue T-shirt,High Quality T-shirt,T-shirt Details, CN Jiangyin Yiqifeiyang Apparel Co., Ltd. , https://www.jyyqfy.com