Gemstones aren’t the only way to punch up -jewelry with pigment. Semitransparent and opaque enamel or hot glass serves as ornament and protective coating—making pieces pop with color. Hand-painted embellishments on gold create covetable designs to be treasured for generations to come. Plus: The age-old technique can be a more affordable alternative to pricier precious gems.   OVER $5,000 (Top) Champlevé enamel cuff with abalone, opals, emeralds, aquamarines, and diamonds; price on request; Masterstrokes by Jewels Emporium, Jaipur, India; 800-103-1841; jewelsemporium.com   (Inset) 18k gold dragonfly in plique-à-jour enamel with diamonds on 18-inch chain; $5,930; Nicole Barr, Raleigh, N.C.; us-info@nicolebarr.com; nicolebarr.com   Jodhpur enamel and aquamarine ring in 22k yellow gold; $6,095; Alice Cicolini, London; anahita@valerydemure