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

Etymology

Origin of conchoidal

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

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 purest flints have the most perfect conchoidal fracture, and prehistoric man is known to have quarried or mined certain bands of flint which were specially suitable for his purposes.

From Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" by Various

The twigs soon become encrusted with a mammelated substance of a red colour more or less deep, nearly transparent, hard, and having a brilliant conchoidal fracture.

From Field's Chromatography or Treatise on Colours and Pigments as Used by Artists by Thomas Salter

The splitting of any body having a structure or line of cleavage: as fir cleaves longitudinally, slates horizontally, stones roughly, smoothly, conchoidal, or stratified, &c.

From The Sailor's Word-Book An Alphabetical Digest of Nautical Terms, including Some More Especially Military and Scientific, but Useful to Seamen; as well as Archaisms of Early Voyagers, etc. by Sir Edward Belcher