Very rare Biedermeier purse circa 1840

Very rare Biedermeier purse (wallet / purse); circa 1840; with beautifully decorated brass folding clasp, presumably set with quartz (rock crystal?) - the clasp is spring-loaded and the spring reacts when opened; the pouch made of black leather (the leather could have been reworked later); traces of use according to age; measurements: 6.5 x 9 cm