by Veronica Crespi Looks like Gucci’s foray into sustainable eyewear was more than a passing fancy. After it debuted a line of bio-based frames synthesized from castor seeds, the Italian luxury house is poised to introduce the first-ever sunglasses made with “liquid wood.” The material, which Benetton currently uses for its hangers, combines wood fibers from sustainably managed forests, lignin from the paper-manufacturing process,…