Actor through long run , accumulate abundant experience , can judge the producing area and quality of the jade from appearance of jade , later on people are used to with the producing area namely the hole , as the good and bad another name of quality of jade 艺人们经过长期使用，积累了丰富的经验，能从玉的外表判断玉的产地和质量，后来人们就习惯以产地即坑，作为玉质优劣的代称，如说“坑子好” ，就是质量好的意思。
