n. 缠丝玛瑙

[ noun ]
an onyx characterized by parallel layers of sard and a different colored mineral
<noun.substance>

Sardonyx \Sar"do*nyx\, n. [L., fr. Gr. ?. See {Sard}, and
{Onyx}.] (Min.)
A variety of onyx consisting of sard and white chalcedony in
alternate layers.