Imitation tourmaline is occasionally seen. The popular watermelon tourmaline and other parti-colored tourmalines are a common target of the imitators. Some assembled imitation stones consist of a thin wafer of colored glass or plastic, glued between two pieces of colorless glass.

These imitations are easy to detect with a microscope or loupe. If the stones are examined along the girdle, the edge of the colored wafer or the glue line can usually be seen. If the stones are examined by looking down through the table, bubbles or debris in the glue plane are sometimes visible.