CAN’T-MISS COLLECTION Queen of Cabochons Daria de Koning’s 8-year-old firm casts a spotlight on the beauty of cabochons. Cut to display maximum color—and sometimes to reveal cool inclusions—her cabochons cluster in soap-bubble formations set off by leggy prongs in 18k yellow gold. The on-trend styles (which start at $500) are American-made, and boast a slightly vintage and whimsical vibe.  From left: Dagny stacking ring in 18k yellow gold with pink tourmaline, rhodolite, red garnet, iolite, and amethyst, $3,600; Dagny Sun earrings in 18k yellow gold with iolite and carnelian, $2,000; Dagny stacking bangles in 18k yellow gold with gemstones, $4,600; Daria de Koning, NYC; 646-543-9020; dariadekoning.com   HOT STOCK TIP Nina studs in 14k rose gold with 0.25 ct. t.w. princess-cut diamonds, $1,