AI'm looking at the picture on my phone, so I can't see it super clearly, but it looks like the top tier may be covered in pearlized gold sprinkles. Wilton has come out with gold, silver, etc.pearlized sprinkles and it looks like that might be what was used.
AYes after I posted I researched and that's what I think it is too!
AI think it looks like crushed nuts, almonds or macedemia maybe? It would certainly go with the olives decorating the cake. Beautiful cake very Mediterranean.