The Proceedings of the Athanasius Kircher Society points us to alphabet agates. Recently a set went for $11,000. Collectors look for and then very carefully cut agates in order to form the letters in the surface. These sets are very rare. I took the pictures and created a banner for the Honest Hypocrite.
I am sure some clever programmer could turn these pictures of agate letters into a a webtool that would allow you to write anything you like in alphabet agates. I just used Paint.
