Our metallic threads are non-tarnishing metal that is wrapped around a core. The Silver and Gold are solid color, Silvery and Bronze are multi-color. The Sparkle Metallic is silk thread with metallic sprinkled on the top. Not sure which color to choose? Try our Metallic Sampler, one section (39 threads in each section) each of Silver, Gold, Silvery, Bronze, Metallic Sparkle.