We decided to visit Craigivar Castle because our hostess told us how interesting it was and it proved true. The first thing you notice is how PINK the tower house is. The process that produces the color is called harling. The castle itself is created from stone but on the exterior a layer of lime based cement has been adhered to it to weatherproof it. Lime is pourous and allows the stone to breath and the moisture to evaporate so that it doesn't get trapped inside the material and damage the stone. While the surface is still wet, the pigment, which is actually red sandstone, is pressed into the material. Thus, Craigievar attained it's lovely pink color. The red sandstone is even in the gravel of the drive giving it a pinkish cast too.