Starfish Fossil
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameStarfish Fossil
Chemical FormulaCaCO3
Mohs Hardness3
Crystal Systemtrigonal
Lusterdull
Streak Colorwhite
CleavageNot applicable to fossil structure; original calcite has perfect rhombohedral cleavage.
Fractureuneven
Specific Gravity2.71
Colorswhite, light gray, gray, brownish-gray
Transparencyopaque
Type LocalityBoulogne-sur-Mer, Pas-de-Calais, France
Mineral GroupCarbonates
Usesscientific study, collector's item, display
Associated Mineralscalcite, clay minerals, quartz
Rarityuncommon
Description
This specimen features multiple well-preserved, five-armed starfish fossils (Astropecten lorioli) in various orientations, embedded in a light to medium gray sedimentary matrix. The starfish are a lighter, off-white color, providing a strong contrast against the darker background.
Geological Context
These starfish fossils date back to the Tithonian stage of the Late Jurassic period (approximately 150.8 to 145.5 million years ago), formed in a marine environment and preserved within sedimentary rock, likely limestone or marl.
