gû-n̂g牛黃

bezoar

bezoar, calculus or gallstone of cattle (a highly-valued substance used in traditional Chinese medicine)

English Wiktionary, “牛黃” (CC BY-SA 4.0) — https://en.wiktionary.org/wiki/%E7%89%9B%E9%BB%83 · confidence: Medium (Wiktionary, Hokkien)