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。