Stun Marks in Natural Stone

Natural stones like marble and granite are just that – completely natural. They are cut from the earth, and formed into slabs or tiles for countertop, floor, and wall use in and around homes. Sometimes during the forming of these stones into slabs or tiles, or after the installation and during normal use, small blemishes may become apparent on the stone. Appearing like scratch marks or white circular “bruises” on the stone, these marks cannot be felt to the touch, nor can they be polished or ground away.


Known as stun marks, these bruises present a serious problem for some homeowners and consumers. Stun marks are created by a sudden hard application of force against the stone, which creates a cascading affect beneath the surface, causing the minerals and crystals to fracture. This shows up as a white mark in the shape of the impact.

Because stun marks go down deep into the stone, it’s difficult to get them out. They can be cut and dug out, and the area filled with an epoxy, but unless the color match is perfect, this solution is often more obvious than the problem itself.

Most homeowners only come to experience stun marks after installation. High heeled shoes, for example, are well known for stunning some types of marble.

Other times, some types of stone such as Calacatta or Bianco Carrara will arrive from the quarry filled with stuns caused when the stone was dug up. In these cases, it’s best for homeowners to be made aware of the presence of the stuns when they are viewing and selecting their slab or tile. Because stun marks are natural and part of the nature of stone, they shouldn’t be viewed as a “defect” in the stone, but merely as part of the natural beauty and variation that all stone can have.

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