Crack

Crack bear carving
MFA# 72.4167

Description

Crack in coffin face
MFA# 72.4732

A visible separation on a surface that extends through one or more layers. Cracks may be due to stress, pressure, temperatures, or humidity variations or mechanical defects. Cracks are described by the size (hairline, wide) and direction (parallel, radial, spiral, etc.). See for example Crackle and Crazing. Geologic terms for cracks include fault, gap, fracture, and fissure. A crack in a textile is mechanical defect due to a missing filling thread.

Synonyms and Related Terms

crevice; chink; gap; cleft; fissure; fracture; cleavage; separation

Additional Images

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  Star crack
  Photo credit: E. Hyslop

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  Hair crack

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  Craquelure

Resources and Citations

• ICOMOS-ISCS: Illustrated glossary on stone deterioration patterns

• For information on cracks caused by humidity and temperature see: M.F. Mecklenburg, Smithsonian Museum Conservation Institute, "Determining the Acceptable Ranges of Relative Humidity And Temperature in Museums and Galleries" Part 1, Structural Response to Relative Humidity and Part 2, Structural Response to Temperature