New Gem Jar Tray Insert For Jewelry Displays, Showcases & Countertops. This is a new gem jar insert that contains removable clear plastic round jars. These jars will hold all of your loose stones, beads and coins. Each gem jar comes with a insert pad inside and lid. Has 50 gem jars. The inside diameter of each gem jar measures approximately 1" (25 mm). The cases measure approximately 14 3/4" x 8 1/4" x 1" (37 cm x 209 x 25 mm). It is recommended that this be used with a display tray