Trilobite Fossil (Walliserops trifurcatus)
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/47445767@N05">James St. John</a> (CC BY 2.0)
Mineral NameTrilobite Fossil (Walliserops trifurcatus)
Chemical FormulaPrimarily calcium carbonate (CaCO3) or silica (SiO2) replacing organic material, often with carbonaceous residues or iron oxides.
Mohs HardnessVariable, typically 3-7 depending on mineralizing agent (e.g., calcite or quartz).
Streak ColorVariable, often dark grey to black or white, depending on composition.
CleavageNone (as a fossil structure), though constituent minerals may exhibit cleavage.
FractureUneven to conchoidal, depending on mineralizing agent.
Specific GravityVariable, typically 2.6-3.0, depending on mineralizing agent.
Colorsdark grey, black, light tan, beige
TransparencyOpaque
Type LocalityMorocco (possibly from Jbel Gara el Zguilma)
Mineral GroupBiogenic/Fossilized Organic Remains
Usesscientific study, educational, collector's item
Associated Mineralscalcite, quartz, clay minerals
Rarityuncommon
Description
A well-preserved fossil of a Walliserops trifurcatus trilobite, featuring a distinctive three-pronged cephalic spine and numerous segmented body plates, presented in dark grey to black against a light-colored sedimentary matrix.
Geological Context
Formed during the Devonian period in marine environments, this fossil represents the mineralized remains of an ancient arthropod, likely preserved through permineralization within sedimentary rock such as limestone or shale.
