Crinoid Fossil
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Mineral NameCrinoid Fossil
Chemical FormulaCaCO3
Mohs Hardness3
Crystal Systemtrigonal
Lusterdull
Streak Colorwhite
Cleavageperfect rhombohedral (3 directions)
Fractureconchoidal
Specific Gravity2.71
Colorsbrown, rusty brown, yellowish-white
Transparencyopaque
Type LocalityMichigan
Mineral GroupCarbonates (biogenic)
Usescollector, scientific study
Associated Mineralscalcite, quartz, limestone, shale
Raritycommon
Description
This is a small, ~0.7 cm cylindrical fossil fragment, likely a crinoid stem, largely covered in a reddish-brown, earthy matrix. Some lighter, ribbed skeletal structures are visible beneath the matrix.
Geological Context
Crinoid fossils are the remains of marine invertebrates that lived attached to the seafloor, commonly found in marine sedimentary rocks such as limestone and shale, indicating ancient shallow marine environments from the Paleozoic Era.
