I used faceted bicone acrylic beads here but I think round beads would work well too. It'll look much more beautiful and sparkly if you use crystal beads (and more expensive too). You can also use one color instead of different colors of beads. And if you use different colors for the 2 square pieces, you'll have 2 looks in 1 pendant! The finished size of this piece measures 2cm x 2cm.
60 3mm faceted bicone beads - grey
32 3mm faceted bicone beads - aquamarine
24 3mm faceted bicone beads - green
Size 11 seed beads - grey
Fishing line (4 lb. weight) - 3 x 40 cm