Sea glass studs 
In cobalt blue Folkestone sea glass 
Made with recycled sterling silver 
In this design the sterling silver wire runs through and around the sea glass making them very secure unlike a lot of sea glass stud that rely on glue to hold the sea glass on. 
Cobalt blue glass was used as far back as the 1809s and uses included poison bottles, medicine bottles, perfume bottles, ink wells. 
With Sterling silver butterfly and post fitting