Up until two days ago (I've been stamping for years), I placed tiles into two categories glazed/ marble tumbled. Each tile is handled differently when stamping. There are even variations based on the inks used (baking/not baking etc). There was a post just two days ago from an SCSr that stated she had used tumbled tiles (not Bottichino) and had Stazon coming off hours after she had applied it. It was the first time I had heard of this. So, I now assume that manufacturer matters, as there is something in the tiles this gal purchased which prevents the Stazon from working as expected. I have never had a problem with Stazon staying put on my tiles--no sealing either (unless I had colored in with chalk). If I were you, Iwould look for the 9-tile box of marble tumbled Bottichino.
Annette
http://stamponthis.com