Known for its colorful, stylish designs, the Italian jeweler Pomellato has unveiled a striking collection of cool white-agate pieces set in 18-karat rose gold. The new designs are a fresh take on the brand’s successful Victorian collection, which features black pieces with gold scroll motifs; but in white agate it has a light, airy appeal for spring and summer. The white-agate designs come in a range of styles, including large-scale earrings, necklaces, and rings, and start at $2,500. (800.254.6020, www.pomell…