Why aren’t slabs more resistant to scratching/cracking/breaking?

[NonSportDaniel]

Originally Posted by steve B

That's true.

So you have access to an FTIR machine? Lots of questions out there that could be answered.
The stamp guys are using xrf and sometimes one other, But the sample area isn't usually big enough to get info without having to wreck an already damaged stamp as a reference (Like to have the data for the paper so it can be backed out of the overall stamp leaving the spectrum for the ink.)

I think that what I might try for the stamp concern is a scanning electron microscope with an EDAX attached. Unless the stamp was oversized you shouldn't have to damage it. Reference would be important for that application as I don't think I could put the composition together from an elemental scan as I don't know enough about the stamp paper composition/ glue backing/ ink top coats in that industry. You might need a combination of tools. The Smith's Detection ATR FTIRs are great, but you would probably crush a portion of the stamp.