It was a pale green ovoid stone.
When attuned, Wong Fei's ioun stone bestowed protection against attacks, increased resilience, and the ability to regenerate wounds.
It was said that Chan Cheng, a god of war in Kara-Tur, once descended to earth in the form of a dragon and challenged Wong Fei Hung, a Shou-ling monk of the Path of Enlightenment. The two battled each other for three days and three nights, and in the end Chan Cheng was so impressed by Wong Fei's skill that he gave him this special ioun stone.
The stone remained with Wong Fei until he died, then disappeared.
It resurfaced in the possession of Sendai, a drow priestess and mage and a Bhaalspawn. She had it with her in her subterranean drow enclave beneath Amn in 1368 DR, when Gorion's Ward confronted her.