Regarding the value of Morfias, regardless of their meaning or significance in some countries like Mauritania or Middle East countries, where for example green eyes will be more valued than blue eyes, or transparency in the bead will matter, my belief is :

1) their size : they are rather big size beads, and as a general rule, the bigger the bead (for islamics) the higher the price,

2) their rarity : one must not forget that for a 1,000 nilas found, you find one islamic. For a 100 islamics found, maybe you find 10 mosaic beads. Now maybe out of 100 mosaic beads, maybe you find one morfia. And maybe out of 10 morfias, one has eyes, and out of 10 eye morfias, one is in good condition and has great colours. figures are obviously just for the demonstration purposes. But it is a fact that they are rare. At any given time, a serious bead dealer may have 20 beads, other average dealers 1 or 2 or none.

3) their complexity : I often compare them to "oeufs de Fabergé" because I believe that almost a 1,000 years ago, they must have been (as they still are) one of the most sophisticated, complex, and beautiful ornaments available then. Bead makers know better but one of the reasons they cannot be reproduced today as yet, is because it would be very difficult and costly. I cannot imagine the value of such a bead back then.

Still today, people believe they are natural, not man-made, and that they fall from the sky with the rain, among many other stories, so if the WONDER is still there, what about some centuries ago?

Yes there are many beads from the islamic period that are almost as attractive and complex and not as expensive but again as a general rule, a good size complex eye bead in good condition will be expensive. Sometimes you find one that didn't catch anybody's attention, or maybe the seller doesn't know the family or the type of bead it is. Sometimes the price varies greatly from one country to another because the tastes are different.

This is only my vision of things of course!