Just found a nice different version again on a strand of Talhakimt...It´s a synthetic one, translucent amber color, 24.6 x 36.5mm...one more for the collection. I´m still looking forward to find some from India on my trips to Morocco...
Second image shows what I got over the years, here and there...Materials are agate/carnelian, synthetic, glass, aluminium. The small one on top is 12 x 18.5mm, the largest white one below 53 x 78mm. They were made in Germany, Bohemia, maybe France and the two bottom right in Africa...