Turritella agate is a unique variation of agate that is most notable for the multitude of fossilized creatures inside of it, notably the shells of the now-extinct Elimia tenera, which was a species of freshwater snail.
Pieces of turritella agate are interesting to look at, as the sections taken from the snail shells are almost like bits from an MRI scan. It's a snapshot of life on prehistoric Earth that also happens to be a beautiful stone. Turritella agate is a perfect gift for someone interested in either gems or fossils, or both! There is a lot to like here.