About half way through my 30 year Greek Island holiday history a Greek resident showed me one of these items. He said they were called the "eye of the sea" and bestowed good luck on the finder of these rare items. I now spend most of my time on holiday looking for these elusive items on the beach (keeps me away from the sun tan boredom and I have found other interesting items in the process - much better than chilling on a sun bed). But I would really like to know exactly what these items are - any help would be appreciated.
The attached photo shows the front and reverse of one of these items - any help would be much appreciated.
Regards, Jays