conchoidal

[ kong-koid-l ]

adjective

, Mineralogy.

1. noting a shell-like fracture form produced on certain minerals by a blow.

conchoidal

/ kɒŋˈkɔɪdəl /

adjective

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

conchoidal

/ kŏng-koid′l /

1. Of or relating to a mineral or rock surface that is characterized by smooth, shell-like curves. Obsidian and quartz often have conchoidal fractures.

Derived Forms

• conˈchoidally, adverb

Other Words From

• con·choidal·ly adverb
• subcon·choidal adjective

Word History and Origins

Origin of conchoidal¹

First recorded in 1660–70; conchoid + -al ¹

Example Sentences

Very compact and fine-grained reddish granular quartz, with a glistening lustre, and flat conchoidal fracture.

From Project Gutenberg

I am told conchoidal white lime-stone meets it on both the east and west sides.

From Project Gutenberg

In the form of translucent fragments, with a highly conchoidal fracture, among the debris of the shores of Lake Pepin.

From Project Gutenberg

At ordinary temperatures ebonite is hard and brittle and breaks with a well-marked conchoidal fracture.

From Project Gutenberg

The fracture of this fossil is perfectly conchoidal, sometimes glossy, and sometimes dull on the surface.

From Project Gutenberg