Nature doesn’t create all types of natural stone the same. Some happen to be more durable and resilient than others, particularly in terms of hardness. Most of the types of stone used as countertop materials will sustain strong impacts without compromising their molecular structure, but things are different once you get into cutting with sharp objects such as stainless steel knives. Many cutting boards are made of natural stone, particularly granite, because they’ll withstand knife strikes without cracking or getting nicked, but they can develop some scratching over time if they’re constantly used for chopping. Seeing scratches on a cutting board, regardless of the material, is something anyone can live with. Nonetheless, you wouldn’t want to see your nice marble countertops getting scratched before your eyes, and there’s always a chance the surface could get chipped when a knife impacts with sufficient force and at the right angle. The Stone Care Experts at Granite Gold® explain why you should avoid cutting directly on your natural-stone countertops.
The Mohs Mineral Hardness Scale
Natural-stone countertops are investments that can boost the value of your property as long as they look good and are free from unsightly scratches. To scratch a stone surface, you need an object that has greater mineral hardness, and this is when understanding the Mohs scale of mineral hardness is helpful. This scale runs from one to seven with the lower measurements being the softest. Diamonds are the hardest on the scale with a factor of seven. Talc is at the bottom with a factor of one. A marble countertop that’s rich in calcite, a mineral that provides attractive veining, has a factor of around four. The Mohs hardness of a stainless steel kitchen knife is around six.
If you have questions about how to care for natural-stone countertops, here’s a short video from the Stone Care Experts at Granite Gold®:
Objects that Can Scratch Natural Stone
You can only scratch minerals with objects that are higher on the Mohs scale, which means a freshly sharpened chef’s knife will certainly scratch marble and limestone tiles or slabs. Hardened steel knives and even a piece of broken glass could scratch granite with enough force. Quartzite is one of the hardest stones you can install on your counters, and they may be able to resist some scratching, but only if you’re certain of its quartz mineral content.
The Potential for Dulling Your Knives
Experienced chefs know some expensive knives should only be used on cutting boards made with specific materials. For example, some sushi knives forged by Japanese blacksmiths aren’t meant to be used directly on hard stone surfaces because they’ll quickly lose their sharp edges.
Other Reasons You Should Use a Cutting Board
Because some natural-stone surfaces are more porous than others, they have the potential to harbor bacteria that could transfer from one food item to another. For this reason, you should isolate food preparation by means of using cutting boards. Finally, the protective seal you should routinely apply to your countertops will weaken faster with constant direct food preparation.
Sealing is one of the most essential steps in caring for granite, marble, travertine, and other types of natural stone. Cleaning and polishing are just as important, and you can take care of both of those tasks at the same time by using a specially formulated granite clean and shine product. To learn more about Granite Gold Clean & Shine® and our other products that are safe to use on all types of natural stone, give us a call today at 1-800-475-STONE (7866).
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Lenny Sciarrino (aka Lenny S) and Lenny Pellegrino (aka Lenny P) grew up in the family business and are co-founders of Granite Gold®.