"Similar to dzi beads are the so-called chung dzi,[4] which have been imported to Tibet since ancient times. These can be plain, naturally banded[5] agate beads, or etched beads (often with black and white striped patterns). Some are carnelians or black agate with thin white etching patterns resembling the back of a turtle, which is an ancient pattern that dates back to the era of the Harappan Indus culture. Ancient Roman agate beads as well as etched Bactrian, Middle Eastern, Chinese, Afghan, Yemeni,[6] and Indian agate and carnelian beads made their way into Tibet. All these are considered chung dzi (in Tibetan, "chung" means ordinary or common). Chung dzi are believed to have similar properties to real "eyed" dzi; they are less valuable, but they are highly prized by Tibetans and also considered a variety of dzi."