Mindat Logo

Chert

This page is currently not sponsored. Click here to sponsor this page.



Colour:Gray, white; black, ...Hardness:6½ - 7½
Name:"Chert, perhaps originally chirt, is believed to be a local English term that was taken into geological use. It may be of onomatopoeic origin. The name chert may be of more recent origin than flint, and unlike flint, is not found in literary usage. It was well established in meaning in 1679 ..." (Frondel, C., 1962, The System of Mineralogy, v. 3, John Wiley & Sons, p. 223.)


A tough, dense rock composed of quartz and few other impurities. The quartz occurs as randomly interlocked, microscopic quartz grains (microquartz) or microscopic grains of fibrous chalcedony.

Chert forms layers and nodules, but also large beds in sedimentary and metamorphic rocks, occurs in epithermal veins, by direct deposition around submarine hydrothermal vents and may form as a product of silicification of biogenic or volcanogenic sediments.

The term "chert" is used for rocks mostly composed of quartz, siliceous precursor rocks of comparable texture are sometimes also called chert, but with the addition of the dominant silica phase, like "opaline chert".

Classification of Chert

mindat.org URL:http://www.mindat.org/min-994.html
Please feel free to link to this page.

Physical Properties of Chert

Lustre:Waxy, Dull
Diaphaneity (Transparency):Translucent, Opaque
Colour:Gray, white; black, brown and other colors due to staining
Streak:White or lightly colored
Hardness (Mohs):6½ - 7½
Tenacity:Brittle
Cleavage:None Observed
Fracture:Splintery, Conchoidal, Sub-Conchoidal

Other Names for Chert

Synonyms:
HornstoneMozarkite
Other Languages:
German:Mozarkit
Simplified Chinese:硅质岩
Spanish:Mozarkita
Varieties:
NovaculiteRibbonstoneTaconite

Other Information

Health Warning:Like all quartz, breathing in fine particles for a prolonged period will produce silicosis.

Internet Links for Chert

Search Engines:
  • Look for Chert on Google
  • Look for Chert images on Google
  • Mineral Dealers:
  • SpiriferMinerals.com - high quality low prices
  • Find Chert on www.crystalclassics.co.uk
  • Wilensky Fine Minerals
  • Top quality minerals from Kristalle of California
  • Buy from McDougall Minerals
  • DAKOTA MATRIX offers Cabinet and Rare Species from Worldwide Localities.
  • Chert specimens for sale - minfind.com
  • Lapis Mineral Magazin
  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • Search for Chert on Well-Arranged Molecules
  • Buy fine minerals and gemstones from Pala International
  • High-end worldwide specimens & outstanding customer service
  • Localities for Chert

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    Mineral and/or Locality  
    Search Google  
    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
    Current server date and time: July 20, 2014 21:54:48
    Mineral and Locality Search
    Mineral:
    and/or Locality:
    Options
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds