乳晶石是在北京西部山区新发现的一种松香岩结晶体石块。小晶体呈不规则的柱状,直径1毫米左右,长短不一,长者可达40毫米以上,短者仅6-7毫米。有的小晶体两端色泽深浅不一、色泽深浅不同的小晶体形成厚薄不一、层次分明的石块。乳晶石的色泽有三种:一为白色; Crystalline stone is a newly discovered rosin crystal stone in the western mountainous area of ​​Beijing. Small crystals were irregular columnar diameter of about 1 mm, the length of the elderly up to 40 mm above the short, only 6-7 mm. Some small crystals at both ends of different shades of color, depth and color of small crystals of different thickness, structured stones. There are three colors of cristobalite: one is white;