Crinoidal Limestone
Image: <a href="//commons.wikimedia.org/wiki/User:Hans_Erren" title="User:Hans Erren">Hans Erren</a> (CC BY-SA 3.0)
Mineral NameCrinoidal Limestone
Chemical FormulaCaCO3 (primarily)
Mohs Hardness3
Streak Colorwhite
Cleavageperfect rhombohedral (for calcite component)
Fractureuneven
Specific Gravity2.71
Colorsdark grey, light grey, white
Transparencyopaque
Type LocalityBelgium
Mineral GroupCarbonates (sedimentary rock)
Usesbuilding material, dimension stone, cement production, collector
Associated Mineralscalcite, aragonite, dolomite, quartz, clay minerals, fossils
Raritycommon
Description
A dark grey sedimentary rock densely packed with numerous light-colored fossil fragments, predominantly crinoid ossicles and other marine shell debris, giving it a speckled texture.
Geological Context
Crinoidal limestone is a bioclastic sedimentary rock formed in marine environments from the accumulation and cementation of skeletal remains of crinoids and other organisms, typically in shallow, clear waters.
