Stone random usually called the squarely or irregular piece of stone as coming from the quarry.
Getting this piece of stone, the cornerstone, and cutting it, creating a new piece of stone, the cornerstone cap, which is cut straight back and front of is natural and wild as coming from the quarry, but still has the volume of the original stone. This way we can show that a wall is built completely of stone, when in fact it is made from other materials ( brick, concrete, etc.) and invested with a cornerstone cap.
With the cornerstone cap can invest walls, pillars, fireplaces, fences, walls, corners of buildings and every where we want to give the impression that our manufacturing is wholly of stone. Random natural face stone is both for indoor and outdoor wall cladding.