Plastic jewelry, also known as synthetic jewelry, is made from materials such as acrylic, polyester resin, polyethylene terephthalate (PET), nylon, and polycarbonate. Design principles for synthetic jewelry focus on color theory, form and function, symmetry and balance, texture and pattern, as well as innovation and creativity. Manufacturing techniques for synthetic jewelry include 3D printing, injection molding, laser cutting, casting, and handcrafting, catering to market and consumer preferences for affordability, durability, aesthetic appeal, customization, and eco-friendly options.