Since the forecast for spring is groovy, be prepared to accessorize in a similarly dyn-o-mite fashion. Think gold medallions on miles-long chains to adorn jumpsuits (rompers are back!) and bold pendant necklaces moving with flowing fringed frocks. This ’70s train has left the station, and it’s waiting for you to get on board with its fun and funky jewelry. 1. Small Cage pendant in 18k gold with 0.69 ct. t.w. diamonds; $3,960; Faraone Mennella, NYC; 212-752-5990; faraonemennella.com 2. Pendant necklace in 18k gold with coral and 0.12 ct. t.w. diamonds; $31,200; Bochic, NYC; 212-632-1700; bochic.com3. 18k yellow gold locket with 0.06 ct. t.w. pavé bail, 0.15 ct. t.w. diamonds on face, and 0.2 ct. t.w. diamond bezels on 25-inch chain; $8,240; Anahita at LUXE Intelligence, NYC; 212-398-9700; anahitajewelry.com  4. Alice ne