What are stones cut in rectangular units called?

Stones cut in rectangular units are referred to as ashlar. This term specifically denotes masonry that utilizes finely dressed stones, typically arranged in a regular pattern with minimal mortar visible. Ashlar blocks are characterized by their uniformity in size and shape, which enhances both structural stability and aesthetic appeal.

In architectural applications, ashlar stonework is often employed in significant buildings and structures, providing a polished and sophisticated appearance. The precision of the cuts allows for tightly fitted joints, making it a preferred choice for walls, facades, and other prominent areas in construction.

The other options represent different types of stones or materials but do not specifically refer to the rectangular cut form. For instance, brick is a molded product usually made from clay, while granite and marble are types of stone but can be cut and shaped in various forms beyond just rectangular units. Therefore, ashlar is the term that best describes stones intentionally crafted into rectangular shapes for use in precise and refined masonry.