These beautiful thimbles have been hand-carved from meerschaum by noted Istanbul artist Sinan Atilla. Meerschaum is a mineral ("a hydrous magnesium silicate"), soft and porous when mined, that hardens when dried. The French term is écume de mer, which like the German meerschaum, means sea-foam, as the mineral is sometimes found floating on the Black Sea. The highest quality meerschaum, used in the thimbles shown above, is mined from the Eskişehir plain in Turkey.
Sinan Atilla's thimbles are superior to any other meerschaum thimbles I have seen. The carving is much more finely detailed, and the beeswax finish gives the thimbles an antique ivory appearance.
Other pieces of his work can be seen at The Art of Meerschaum, and are for sale at Turkishtulip.com and occasionally on eBay.