rimstone
/ˈrɪmstoʊn/Definitions
1. noun
A type of stone used in traditional Scottish and Irish architecture, typically a type of flagstone.
“The old Scottish castle was built using rimstone and other local materials.”
2. noun
A type of stalagmite or stalactite formed from the calcite-rich solution dripping from the ceiling of a cave.
“The rimstone in the cave formed over millions of years through natural geological processes.”