This is an antique Art Deco period "match safe"--a water-resistant container for matches, but could be used to hold any little keepsake. It's made of 900 purity silver, with a sugarloaf sapphire button (probably synthetic). I unfortunately can't recognize the hallmarks or serial number, but I've taken close up photos of them.
The closure mechanism is tight and beautifully constructed, all handmade, dating to around the 1920s. It weighs just over 20 grams.
