First of all, it is such a beautiful necklace written in, so please allow us to show it here! 🙂
Second, the thing in common is that they belong to some of most noble friends of Prophet Mohmmed’s (in Arabic). All but the 5th are Ansar or early Muslims of Medina, Oqba however is from Qudhaa’a tribe.
Third, you might want to know more about these selected Sahaba individually, so here you are: