The Marquis of Sui's pearl or Chinese Suihouzhu (Suí-Hóu-Zhū, 隨侯珠) was a famous gemstone in a Warring States period (475-221 BCE) folktale about a ruler of Sui state who was given an amazing luminous pearl by a grateful snake whose life he had saved. In the history of folkloristics, this legend is the earliest known example of the "Grateful Animals" motif. The Marquis of Sui's pearl, which is frequently paired with another famous regalia, the Heshibi, became a literary Chinese metaphor for underestimating a valuable person or thing.