Traditional mahjong construction materials include bone backed with bamboo, and modern sets often feature Bakelite, celluloid, Catalin and composite wood or paper. Less common materials found in high-end sets include jade and ivory.
Plastic tiles, including Bakelite, celluloid and Catalin varieties, often feature rounded edges and have a familiar plastic appearance. Bakelite tends to have more of a butterscotch coloration than other plastic types, and Catalin often appears less opaque than Bakelite. Celluloid tiles are somewhat rare as the material was largely phased out before mass-produced mahjong tiles became commonplace. They often have a camphor smell.
Checking for Haversian lines in bone pieces can confirm the material type. These lines are what remain of the blood circulation systems that once kept the bone alive. Pieces made from reconstituted fish bone may or may not have these lines.
Ivory mahjong tiles are extremely rare. Experts can help identify ivory pieces, which may be very valuable. A ban instituted in 2014 makes it illegal to sell ivory items in the United States.
Jade pieces feature the characteristic weight and feel of stone, and most mahjong sets are made of white jade or black jade, also known as nephrite, instead of the standard green jade. These may have symbols carved into the face of each piece instead of painted on them.