This material, with its distinctive black and mottled beige coloring is unusual, and has been imaginatively used by the carver. It comes from a range of stones found as pebbles and highly regarded by the Chinese since ancient times. Chinese jade carvers of the later dynasties were skilled at using variations in color in the stone to accentuate their designs.
The material is reminiscent of a range of marble mined in Yunnan province and more commonly known as "Dali stones", a material beloved of the literati where natural pictures exist in the stone when appropriately sliced.
The flute is a symbol of Han Xiangzi, one of the Eight Immortals, while the gourd in this case brings to mind another of the Immortals, the lame beggar, Li Tieguai. The design is intended to evoke the Immortals in general.