Mineral Identification...Hardness 

I have some stones that can't be scratched by corundum even by diamond. I have no idea what stones they are. They do not seem like diamond at all. I have just uploaded the testing video.

Nice!

👍👍👍🥰🥰🥰🥰

Are the ceramic testing plates harder than your glass scratch test plates then? Hard enough to cause most minerals to streak rather than scratch? What would happen if you used something like corundum on one of those ceramic plates?

my students insist they want to witness the scratch test for the orange mineral aka cheese block :O

But does glass scratch glass? What if my "quartz" is actually glass and glass scartches glass?

Thx

Gd

Mera pass b hi

Thx