Cylindrical copper vase

At first glance, one could think of a shell casing reworked in the "art of trenches" way but given its diameter (110 mm) and especially its material (copper sockets, should not exaggerate!), I lean more towards an isolated artisanal manufacture. It is also difficult to comment on the way in which its surface was treated... Probably acid but with what method to obtain these resolutely abstract patterns? The bottom is made of thick brazed brass and ensures good stability. Beautiful original object, easy to maintain (miror) for copper lovers!