wallstone means stone used for building, especially in the construction of walls. Lexicurio rates it Sui generis — a strength score of 96 out of 100.
Etymology
From Middle English walle ston, from Old English weallstān (“stone for building”), equivalent to wall + stone.
noun
- Stone used for building, especially in the construction of walls.“In the upper stories the walls are built hollow, the utilised internal linings of brick, and the outer walling built of coursed rubble wallstones from the old demolished building, […]”