Pisolite
![Pisoids in the Conococheague Limestone (Upper Cambrian) of eastern Pennsylvania](/Images/godic/202502/03/PisolitesConococheagueUpperCambrian4509.jpg")
![Pisolitic limestone; Itaboraí, Rio de Janeiro, Brazil; pisolith diameters average 1.0 cm](/Images/godic/202502/03/Calcario2EZ4509.jpg")
![QEMSCAN mineral map of pisoids](/Images/godic/202502/03/Qemscan_pisoliths4509.png")
A pisolite is a sedimentary rock made of pisoids, which are concretionary grains – often of calcium carbonate, but sometimes of rarer minerals – which resemble ooids but are always more than 2 mm in diameter. These grains are approximately spherical and have concentric layers reaching 10 mm in diameter.