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Of, relating to, or being a surface characterized by smooth, shell-like convexities and concavities, as on fractured obsidian.

[From Greek konkhoeidēs, mussellike : konkho-, concho- + -oeidēs, -oid.]

con·choi′dal·ly adv.


1. (Geological Science) (of the fracture of minerals and rocks) having smooth shell-shaped convex and concave surfaces
2. (Geological Science) (of minerals and rocks, such as flint) having such a fracture
conˈchoidally adv


(kɒŋˈkɔɪd l)

denoting a fracture shape whose surface resembles the inside of a clamshell, characteristic of certain minerals.
con•choi′dal•ly, adv.
References in periodicals archive ?
SEM images indicate a high degree of conchoidal fracturing, possible triple point morphology typical of tripoli, and particle sizes ranging from 10-30 microns.
The best quality were deemed to be of French or English origin, translucent with a smooth surface of a "uniform tint of light yellow or brown color, and slightly conchoidal fracture.
Modifications induced by fracturation are percussion striae; inner conchoidal scars, some with adhering flakes; anvil striae on the shaft of larger long bones; internal vault releases and concentric fracture cracks on the skulls; crushing of spongy bones; and peeling, predominantly on vertebrae, ribs, scapulae and coxal bones.
Along with the carbon, broken and irregular fragments of glass shards exhibiting uneven to conchoidal fractures have been noticed in the limestone samples (Fig.