Glass Top Jewelry Display Case Box White 50 Gem Jars. Glass Top Display Case. This is a new glass top black display case. The glass top allows you to display your contents while keeping them dust free and secure. The latch on the lid helps keep you from losing any items. It measures approximately 14 3/4" x 8 1/4" x 2 1/8" (37.4 cm x 20.9 cm x 53 mm). Gem Jar Tray Insert. This is a new gem jar insert that contains 50 removable clear plastic round jars. These jars will hold all of your loose stones, beads and coins. Each gem jar comes with an insert pad inside and lid. The inside diameter of each gem jar measures approximately 1" (25 mm). The insert measures approximately 14 1/4" x 7 3/4" x 3/4" (36.2 cm x 198 mm x 19 mm).