How to test if the glass fully tempered?

In daily application, fully tempered glass has 5-6 times hardness than regular glass. But by visual, we couldn't identify whether tempered or not(of course there's a way to use polarizing film by experience stuff). Also how we can know if the glass tempering enough to meet requirement?

Break it! By using hammer or special pen, the tempered glass will become small particles, follow standard ASTM C429-21(2025) to count the particle quantity under a square 50x50mm against different thickness to see if particle quantities can meet with standard, see below video how to make this test