A sun-kissed model spies a treasure chest on a sandy beach. Peering inside, she finds the most beautiful gold locket, studded with tiny diamonds; silver earrings made to look like coral; and a magnificent fish bone bracelet.A foxy guy (sans shirt, of course) appears and fastens the locket around her neck in slow-mo. Cut.Should Sarah Greenberg — the Oakland-based designer behind Sarah Swell — need a commercial director, we’ve got her covered. Her organic, inspired-by-nature jewelry line gives rise to impossibly romantic notions.Delicate “worry stone” stacking rings, for instance, look like they’ve been affixed with irregular beach pebbles and a medallion that appears to be attached with tiny barnacles. Greenberg’s meticulous handcrafting is evident in even the tiniest details, like the toggles and clasps.Despite her careful work, the pieces are still highly affordable.Hardly a tough sell.Available at Monkey, 2025 Chestnut Street, at Steiner Street (415-788-7885); online at sarahswell.com.