Mohs hardness is a scratch test. It shows which reference minerals can scratch a tile surface. For vitrified tiles it is a declared value from the manufacturer, not a pass or fail requirement of EN 14411.
The number is useful as a rough comparison between surfaces. It is not a full measure of how a floor will wear, so read it alongside the abrasion rating.
How the Mohs scale works
The Mohs scale ranks ten minerals from 1 to 10. Each one can scratch those below it. Talc is 1, feldspar is 6, quartz is 7, corundum is 9 and diamond is 10.
The scale is ordinal. The steps are not equal, so a 7 is not "one step harder" than a 6 in any even sense. Diamond, at 10, is far harder than corundum at 9.
Quartz at 7 matters most for floors. Sand and grit brought in on shoes contain quartz, and grit is what scratches floors in daily use. A surface that resists quartz resists most everyday scratching.
How tiles are tested
The test method for tiles is EN 101. The tester draws the point of each reference mineral across the surface and records the hardest one that does not leave a scratch.
European data sheets list Mohs under EN 101 as a declared value. That means the standard asks the maker to state a figure if it declares one, but sets no minimum. Indian factories often print a Mohs value on catalogues as well.
Glazed and unglazed surfaces behave differently. On a glazed tile, the result is the hardness of the glaze. On full-body or unglazed porcelain, it is the hardness of the body itself.
What the number tells you
- It shows how well the surface resists a single scratch from a hard point.
- It does not show how fast a surface wears under repeated foot traffic; that is the abrasion test.
- It does not show how a polished surface keeps its gloss, which depends on the polish and any coating.
- It does not show resistance to chipping from a dropped object, which depends on strength and thickness.
For floor wear, the main measure for glazed tiles is surface abrasion to ISO 10545-7, reported as a PEI class. For unglazed tiles it is deep abrasion to ISO 10545-6. Read what PEI rating you need for that side of the question.
What to ask the factory
- Ask whether the Mohs value was tested to EN 101, and by which laboratory.
- Ask whether the result is for the exact finish you are buying, since gloss, matt and carving glazes differ.
- Ask for the PEI class or deep abrasion result as well, because it matters more for floors.
- Treat a Mohs figure printed on a box or catalogue with no report as a claim, not a test result.
For high-traffic areas, the full set of checks is in floor tiles for commercial and heavy traffic.
Next step
We check that test reports match the product and finish you are buying, and arrange independent tests when needed. To set the right checks for your range, book a free sourcing review.