Which type of mortar is specifically designed for stone masonry?

Type M mortar is specifically designed for stone masonry due to its high compressive strength and lower water retention properties. This type of mortar is formulated with a higher cement content, which provides superior bonding strength necessary for supporting heavy stone units. Its dense nature makes it ideal for applications where stones may experience significant loads, such as in foundations or retaining walls.

This mortar is less workable than other types but excels in applications requiring strength and durability. While other mortar types, like Type S, Type N, and Type O, serve their respective purposes—such as for general masonry, exterior walls, or historical restoration—they do not have the same level of compressive strength suitable for stone masonry, making Type M the preferred choice in such scenarios.