11 mm Acrylic Dark Amethyst Tri Beads Bulk 1,000 Pieces. We carry a huge selection of Tri beads of over 30 colors at bulk wholesale pricing. Tri-beads are made from plastic which makes them an affordable craft for jewelry projects including ornaments, keychains and bracelets. Tri means three so these beads have three arms. When Strung together they interlock. Perfect for kids arts and crafts.