一切經音義 2.54

2.54

珂貝（可何反礦石類也次於玉也埤蒼云珂馬腦也或云潔白如雪所以用纓馬[腐-付+隹]也貝者螺貝也一名貝齒珠也今取白色為喻）。

Corals and cowries (珂貝: [珂 is] *k'ā* + *hâ* = *k'â* [ke-he]. It is a kind of mineral stone, secondary to jade. The Picang says: '珂 is agate.' Some say it is pure white like snow, hence used to ornament a horse's reins. As for 貝, they are spiraled shells, also called 'cowrie-tooth pearls'. Here it is taken as a metaphor for whiteness).