Costume jewelry is routinely sold in lots, which are large groups of mixed styles and pieces, from necklaces to bracelets to earrings. For sellers, listing a large collection of inexpensive costume jewelry is preferable to auctioning each item one at a time. For buyers, purchasing costume jewelry by the lot has numerous appeals. For example, some people make new pieces of jewelry out of old ones, so lots offer these buyers an opportunity to acquire a great deal of inventory in a single transaction. Other buyers scour costume jewelry lots for high-quality items to repair or refurbish. Whatever the reason, lots are generally sold by the total number of pieces or by weight.

During the 1920s, costume jewelry began infiltrating the mainstream fashion world thanks to the spread of affordable materials and improved production methods. Coco Chanel’s line of eye-catching jewelry transformed the public image of such fashion accessories. Instead of symbolizing wealth or family heritage, Chanel’s jewelry were designed to project a specific aesthetic or sense of style.

Companies like Trifari and Miriam Haskell quickly followed Chanel’s lead, and the market for costume jewelry exploded. Meanwhile, out in Hollywood, the over-the-top, gaudy, fake gems made by a designer named Joseff gave the genre glamour. Film stars such as Mae West, Joan Crawford, and Marlene Dietrich wore costume jewelry both on screen and off...