Oyster Chest (Magic Chest)

This item appears to be a small, squat wooden chest, 2' in length along any side. The inside of the chest is lined with red velvet in many soft, cushiony folds. Hidden between the folds is the command word, sewn into the velvet itself. If from one to five grains of sand are placed within the folds inside the box and the command word is spoken, the chest magically locks itself and does not open again until the command word is repeated. During the time that the chest is locked, it begins to turn the grains of sand into perfectly formed, nonmagical pearls. For each consecutive day that the box is left undisturbed, each pearl increases in value by about 3 gp. Thus, after a week, each pearl would be worth 21 gp; after a month, each would be worth 80-100 gp. If the box is left unopened for longer than one year, there is a 1% cumulative chance per day thereafter that the growing pearls become misshapen and worthless.
Casting dispel magic on the chest does not open it, but successfully casting a knock spell against 14th-level magic does. However, the pearls inside immediately disintegrate. If the chest is ever broken, it loses all of its magical properties forever. 
Category:Encyclopedia Magica Magic Items
Category:Magic Items
Category:Magic Charms