Tibetan dzi contain elements of jade and agate, belonging to the nine-eyed cavenous rocks. The colors can generally be categorized into dark and light brown, its patterns are generally milky white lines etched to its inner core. Some Dzi researchers regard the inner color of the Dzi's string hole as an important criterion for judging the quality of the Dzi. Milky white color is more superior in quality, and thus more precious.

Due to weathering, dzi 's surface appears scaly with cinnabar dots and chippings. As it is passed down and worn by different collectors, and given blessings from monks, it will appear naturally smooth and lustrous from the interior to the exterior. Basically, its authenticity can be determined based on the smoothness, luster, weathering marks on the surface, chippings, curves and the technique of making the string hole of the 's opening as well as from the line designs.