conchoidal

American  

[kong-koid-l] / kɒŋˈkɔɪd l /

adjective

Mineralogy.

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

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conchoidal British  

/ 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

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conchoidal Scientific  

/ 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.

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Other Word Forms

• subconchoidal
  adjective
• conchoidally
  adverb

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Etymology

Origin of conchoidal

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

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Example Sentences

See Examples For:

conchoidal

Mineral fracture surfaces may be rough, uneven, or show a conchoidal fracture.

From Textbooks ● Jan. 1, 2017

A conchoidal fracture has a smooth, curved surface like a shallow bowl or conch shell, often with curved ridges.

From Textbooks ● Jan. 1, 2017

The fracture is conchoidal, and the material is brittle.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 3 "Convention" to "Copyright" by Various

Your glance caught a wave passing amidships as a heaped mass of polished obsidian, having minor hollows and ridges on its slopes, conchoidal fractures in its glass.

From The Sea and the Jungle by H. M. (Henry Major) Tomlinson

It has a conchoidal fracture, and is infusible, which distinguishes it from compact felspar.

From Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology by Sir Charles Lyell

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