Bakelite was an early plastic resin, developed by Leo Baekeland in 1907. Originally used for industrial purposes thanks to its ability to withstand heat, molded Bakelite and its cast cousin, Catalin, made the jump to costume jewelry in the 1920s and had their heyday in the 1930s and ’40s. Costume-jewelry manufacturers were attracted to Bakelite for numerous reasons. First, it was hard enough to cut and polish, which made it a terrific choice for everything from brooches to beads to bracelets, its most popular application. Techniques ranged from scratching the surface lightly in repeated or decorative patterns to outright carving. Some carved pieces have deep valleys and furrows; others sport patterns that suggest the outside of a pineapple or the facets of a jewel. Equally appealing was Bakelite’s range of colors, which were given names like Creamed Corn, Butterscotch, Egg Yolk, and Salmon. Some types of Bakelite were marbled—Mississippi Mud, Creamed Spinach, and Chocolate Sundae capture the character of these mixed hues beautifully. Less common was translucent Bakelite in Root Beer, Lime Jell-O, and Cherry Juice. While some Bakelite costume jewelry was fashioned from solid blocks of a single color, many more began as laminated pieces, in which horizontal or zigzag layers of complementary colors were combined. Sometimes pieces were laminated to create polka dots; other times polka dots were hand painted on an object’s surface, and in the 1950s polka dots and gumdrop shapes were injected into Bakelite during the manufacturing process itself. Of the brooches and pins, one of the most popular treatments during the Art Deco 1930s was to combine Ebony Bakelite—an imitation of the jet pieces from the Victorian era—with rhinestones or inlaid silver. Egyptian motifs were in vogue, as were pins in the shapes of animals (cats, camels, dogs, birds) and plants, especially flowers and clusters of dangling cherries. Especially collectible are the World War II era MacArthur Hearts, which consisted of a 3-by-3-inch key-shaped pin, from which dangled a puffy red heart with a keyhole in its center—it was sold with a card that read "He holds the key to my heart." The most famous use of Bakelite in jewelry was as bracelets. Many of these were formed of large, block- or medallion-shaped beads that were strung together on strips of elastic. Other Bakelite bracelets were hinged, carved into the shapes of serpents, or left open at the back so they could be easily slipped onto a wrist. Some bracelets incorporated chrome accents into their designs, others combined Bakelite with Czech glass. But the most collectible types of Bakelite bangles are the so-called Philadelphia bracelets, which take their name from a Philadelphia auction in 1985 that featured two of these remarkable pieces. Philadelphia bracelets are always laminated in colors that include green, red, and yellow. The best pieces are hinged, and feature either multicolor laminated wedges or individually colored slices that have been glued onto the bracelet body, which is usually a rich shade of Butterscotch.