Swarovski sew on crystals Navette (3223) in Emerald are loose flat backed crystals that come with a thread hole, enabling the crystals to be sewn onto fabric. Swarovski Navette shaped crystals have an elongated, oval shape with pointed ends that resemble a small canoe or a leaf. They have a flat top surface and bevelled edges that create a multi-faceted effect, giving them a sparkling and radiant appearance.