Platinum band with Gibeon meteorite inlay and 0.96 ct. t.w. black diamonds, $5,600, lashbrookdesigns.com   One-of-a-kind heart-shape blue sapphire ring in 18k rose gold, $5,020, ireneneuwirth.com     Per Lei emerald-cut engagement ring in platinum, $1,920 (without center stone), danhov.com     14k yellow gold men’s milgrain band with 1 ct. t.w. diamonds, $3,650, sylviecollection.com   Ring with 1 ct. fancy yellow diamond and 0.88 ct. t.w. round diamonds in 18k gold, $15,050, supremejewelry.net