conchoidal

詳細解釋：

con.choi.dal

adj.（形容詞）
Of, relating to, or being a surface characterized by smooth, shell-like convexities and concavities, as on fractured obsidian.
貝殼狀的：（屬於）表面光滑且呈貝殼狀凸凹特點的、或與之有關的，如黑曜石碎塊

來源：
From Greek konkhoeidôs [mussellike]
源自 希臘語 konkhoeidôs [貝殼狀的]
konkho- [concho-]
konkho- [前綴，表.貝類的.]
-eidôs, -oeidôs [-oid]
-eidôs, -oeidôs [後綴，表.貝形的.]

【引伸】
conchoi.dally
adv.（副詞）