Hello- I can not find specific scientific answer for you. The MOHS scale shows hardness but there is no practical reference to individual marbles by name.

I did speak to our fabricator for his opinion. He said that while polishing it, it appears to be on the "harder" side compared to many other marbles. He did caution that although it may be slightly "harder", when speaking about any marble's durability, they are ALL relatively "soft" compared to granite.

Hope this helps!