Fracture in mineralogy is the texture and shape of the surface formed when the mineral is fractured. Fracture differs from cleavage and parting, which involve clean splitting along a plane surface, as it produces rough irregular surfaces [Ref1]. The appearance of fracture surfaces among minerals is highly varied and is a useful tool in identification. In this part of my Blog I’ll describe the fracture surfaces broadly seen in minerals.

Conchoidal fracture is characterized by smoothly curving nested arcs as those on a  seashell[Ref2].

Earthy fracture results in dull, clay-like surfaces without crystalline appearance[Ref2].

Fibrous fracture is typified by elongated crystal forms[Ref2]. 

Granular fracture is produced in aggregates of crystals[Ref2].

Hackly fracture produces torn edges and surfaces[Ref2].

Irregular fracture presents an irregular fracture pattern[Ref2]

Splintery fracture produces thin long cleavages or partings[Ref 2].

Uneven fracture features flat surfaces in a random pattern[Ref2].

REFERENCES

Ref1 . https://en.wikipedia.org/wiki/Fracture_(mineralogy)

Ref 2. http://csmgeo.csm.jmu.edu/geollab/kearns/Minerals/Fracture.html

Ref 3. https://www.pinterest.com/pin/109564203407418361/

Ref 4. https://www.mindat.org/min-3337.html

Ref 5. https://en.wikipedia.org/wiki/Fracture_(mineralogy)#/media/File:Limonite_bog_iron_cm02.jpg

Ref 6. https://www.mindat.org/min-2402.html

Ref 7. https://en.wikipedia.org/wiki/Fracture_(mineralogy)

Ref 8. https://www.mindat.org/min-975.html

Ref .9 https://sanuja.com/blog/ore-minerals-and-rocks

Ref 10. https://www.mindat.org/min-305.html

Ref 11. https://geology-fundamentals.fandom.com/wiki/4241978/hackly-fracture

Ref 12. https://www.mindat.org/min-1209.html

Ref 13. http://www.pitt.edu/~cejones/GeoImages/1Minerals/1IgneousMineralz/Feldspars.html

Ref 14. http://webmin.mindat.org/data/Plagioclase.shtml#.YADaz-BlCV4

Ref 15. https://www.minerals.net/Image/2/9/Actinolite.aspx

Ref 16. https://www.mindat.org/min-18.html

Ref 17. https://www.minerals.net/mineral_glossary/uneven_fracture.aspx

Ref 18. https://www.mindat.org/min-3701.html