Rubble Masonry: Rubble masonry is the simplest and most basic type of stone masonry. It involves using rough, irregularly shaped stones of various sizes and laying them with mortar or without mortar. Rubble masonry can be coursed (with roughly equal-sized stones) or random (with stones of different sizes and shapes).
Ashlar Masonry: Ashlar masonry is a more refined and uniform type of stone masonry. It uses precisely cut and dressed stones with flat faces and straight edges.