Burgess Shale Fossil
Image: James St. John (CC BY 2.0)
Mineral NameBurgess Shale Fossil
Chemical FormulaPrimarily hydrous aluminosilicates (clay minerals), SiO2 (quartz), and organic carbon.
Mohs Hardness2.5
Crystal Systemamorphous
Lusterdull
Streak Colorgray to black
CleavagePerfect fissility (splits into thin layers)
Fractureuneven to splintery
Specific Gravity2.7
Colorsdark gray, black
Transparencyopaque
Type LocalityBurgess Shale Formation, Walcott Quarry, above Field, British Columbia, Canada
Mineral GroupSedimentary Rock (Fossiliferous Shale)
Usesscientific study, education, collector
Associated Mineralsclay minerals (illite, chlorite), quartz, pyrite, organic matter
Raritylegendary
Description
The image displays two dark, well-preserved fossil arthropods, Waptia fieldensis and Marrella splendens, embedded within a dark gray, finely layered shale matrix. The fossils appear as flattened carbonaceous films.
Geological Context
The Burgess Shale is a Middle Cambrian Lagerstätte renowned for its exceptional preservation of soft-bodied marine organisms, offering a critical glimpse into the 'Cambrian Explosion' and early animal evolution. It formed in an anoxic deep-water environment at the base of a submarine cliff, which facilitated the unique preservation.
