Can Granite Be Used Under Chairs With Metal Legs?

Moh's Scale

• The universal scale to test the hardness of a natural stone such as granite is known as the Moh’s scale, based upon the research put forth by mineralogist Frederick Moh out of Australia. The scale determines the hardness of a material by comparing the scratch resistance of one material to another, and is only used to define durability according to abrasive forces. According to Moh’s scale, any material that is higher on the scale will scratch something below it, but not vice versa.

The Hardness of Granite

• Granite normally rates around a 6 on Moh’s scale, although it is usually grouped in with orthoclase and feldspar. It can be rated as a 7 if it includes particles of quartz. At a 6 on the scale, granite is one of the harder materials known, and while a knife will not scratch its surface, some items such as glass or quartz, will leave a mark.

Natural Flaws

• As a general rule, the metal from chair legs will not scratch the surface of granite tiles due to the inherent abrasive resistance of the material. However, if there are natural flaws in the surface of the stone, such as a crack, there is the possibility that aggravated abrasion over the years will eventually cause slight scratching.

Exceptions to the Rule

• You should be fine using chairs with metal legs on top of a granite floor, but the introduction of additional materials could cause scratching. For example if you break a drinking glass and the a tiny sliver of glass is caught under the edge of a metal leg and dragged across the surface of the floor, there will certainly be a scratch.