How marble and granite slabs get their shine

While marble and granite countertops in people’s homes appear very glossy, this is actually not a natural property in the material. Marble and granite slabs do not come looking like that straight from the quarry. The truth is that marble and granite countertops have been polished to look so glossy, but they are actually course and shine-less when they are found in the Earth.

Since marble and granite slabs are natural stones, they are composed of crystals, which contain assorted minerals that are locked together. Marble and granite slabs look and feel rougher when they are quarried in various locations around the world. Luckily, California is one of the locations where marble and granite are found, so California granite countertops are available to American homeowners.

Marble and granite slabs are made by using a series of graduated grinders, which are normally made from industrial diamonds. To start the process, a very rough one is used, starting with glass paper that is very coarse and gradually becomes finer and finer. Ultimately, the goal is to create slabs that can be used to make marble and granite countertops. The grinding is actually cutting the rough edges off of the stone by scratching it, and as the diamonds become smaller and smaller the scratches become finer. The crystals are worn down until they eventually form perfectly flat marble and granite slabs.
The gloss and shine of marble and granite slabs are similar to a mirror, which is why the slabs must be perfectly flat to reflect that sheen. If the crystals are flat then a perfect image is reflected back, and the marble and granite countertops look incredibly shiny. If the surface is rough and the reflected light ceases to give a perfect reflection, the marble and granite slabs begin to dull. So the shine that is applied to those marble and granite countertops can be lost after a great deal of use.

In order to get the shine back in those marble and granite countertops, the stone must be ground down again. The shine on marble and granite slabs is not the product of adding some chemical to the stone, but is a property of the stone itself. The harder the stone, the more difficult it is to grind down and the greater degree of shine can be achieved. This is why polished marble and granite countertops have the greatest degree of shine.

People have been using similar techniques to grind down marble and granite slabs for millennia. The ancient Greeks were probably the first people to realize the possibilities in marble and granite slabs, since they used them for countertops, floors, walls, columns, staircases, mantels and sculptures. The stones may look rough when they are first quarried from the Earth, but after the process they are perfect for shiny marble and granite countertops.