In addition to jade, other precious and semi-precious stones such as agate, amber, emerald and crystallized quartz were used by craftsmen to carve intricate seals.
它的硬度近乎玉，鐫刻起來事倍功半，但它色澤美麗、紋彩斑斕，有人拿來治印，大都只為觀賞、把玩，實際上拿來鈐蓋的並不多。