This fantastic item is a large 19th century battle axe, known as a Tabarzin, that was made in Bikaner, in North-West India. The head of the axe is engraved with floral decoration, and is punched around. The exquistitely ornate handle is chased with gold along its length, and is adorned with dense and intricate floral scrolls.
The base of the axe unscrews to reveal a beautiful hidden dagger. The blade extends approximately a third of the axe's full length, and the sharp steel is complemented superbly by the gold of the pommel at its hilt. A very similar piece was sold at Sotheby's Arts of the Islamic World auction, in October 2017.
Other such axes, from the 18th and 19th century Islamic and Indian worlds can be found in the V&A's collection, for example this exquisite piece. The Wallace Collection, London is also the home of similar works, another particularly beautiful example is OA1560, which also dates to 19th century Northern India.