How To Use The MOHS Hardness Test Set On Glazed Tile

mineralab test kit

First opening and testing of this high quality kit from mineralab

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Ever wanted to know what the technical characteristics of a tile were but were afraid to ask or did not have the time to research it?  I did.  Working in the industry for a couple of years, I’m a bit embarrassed I did not know what they really meant. I did not consider the technical side of a tile and only looked at wether it was porcelain or ceramic. Whether it looked nice and have a sellable color were my main concerns.   And of course it the tile was of “peak value” in terms of what you get for your hard earned money.  These are important considerations and they are often the strongest drivers for a consumer to choose a tile.  I know it is for me.  However I always knew that in the project markets where architects specified material, the technical characteristics of a tile mattered. And this is for good reason. The tile has to perform better in a tougher envirnoment. Often times the projects are commercial and so most likely there will be a huge amount of foot traffic.  Often times the tiles has to go through many freeze thaw cycles in cold climates such as the mid-west of the Unite States.

The MOHS characteristic tells you how hard the glaze of the tile.

This information is useful to measure relative durabilty so comparisons can be made.

But thanks to this kit I have a better idea of what MOHS means through direct hands on experience.

I’m glad I spent the money for this kit even though it was a little on the high side. By the way if anyone reading this would like to test this kit in person, Summit Tile is happy to share this kit with you. Just ask or stop by our location. In the video I test a shiny glazed tile that is rated MOHS 4. 


MOHS has a scale of 1 to 10

Some common things that with a MOHS rating:

• Fingernails- 2.0
• Penny- 3.0
• Knife blade- 5.0
• Glass- 5.5

The ratings assigned to different materials are no proportional to their scratch resistance in comparison to each other. For example, the hardest element with a 10 on the Mohs hardness scale (diamond) is 4 times harder than an element that measures 9 (corundum); whereas a 4 on the scale is only about 10% harder than a 3. Since the Mohs hardness scale is a relative scale and not an absolute scale, the numbers assigned to each element should be used for reference purposes only. – Contempo Floor Coverings

ASTM does this test and they are scientific

SPECIAL HARDNESS TESTING PROCEDURES INCLUDE THE MARTENS scratch hardness determination as well as the Mohs scratch hardness. In the Martens procedure, a specimen surface under a specified test force is scratched by a diamond cone with a 90-deg apical angle. The test force F is varied until a scratch width of 10 μm is microscopically measured. In this way, a particular scratch hardness value can be attributed to the specimen.

MOHS Scale from soft to hard ( 1 -10)

  1. Talc
  2. Gypsum
  3. Calcite
  4. Fluorite
  5. Apatite
  6. Feldspar
  7. Quartz
  8. Topaz
  9. Corundum
  10. Diamond

Stop by Summit Tile and get hands on experience with a MOHS test

Its fun testing and confirming manufacterers rating of a tile. Breaking stuff is fun! Messing around is fun. There is plenty of scrap tile here so why not give it a try.

You’ll be surprised how hard it is to perform this test

what national floor covering alliance has to say about the MOHS test

MOH’s Rating Scale (Method of Hardness):
The relative hardness of glazed tile is an important issue that should be addressed when selecting a tile. The test is performed by, scratching the surface of the tile with different minerals and subjectively assigning a “MOH’s” number to the glazed.
The softest mineral used is talc (a # 1 rating if no scratch), the hardest is a diamond (a # 10 rating if no scratch). Other minerals that provide MOH’s values of five or greater are suitable for most residential floor applications; a value of seven or greater is normally recommended for commercial applications. Both abrasion resistance and glaze hardness should be addressed when considering using glazed tiles as floor products.

What does MOHS stand for anyway?s

It is named after a German geologist in 1812, Friedrich Mohs becasue he created the scale. Wiki Ref.