Thank you for submitting your item for appraisal. This appears to be an archaistic shang / western zhou-style Chinese bronze zun ritual vessel of short trumpet form with flared rim and protruding flanges, the body with taotie-mask design in relief, most likely produced in the 20th century. The rim appears to be cut down, flaws in the metal cast grinded off, patina most likely artificial, I can see no malachite green or cuprite encrustation . If you had been hoping that this could be authentic, you would need an X-ray fluorescence spectroscopy to be sure. Any larger auction house could do this for you. Any proof of provenance in writing would also be necessary, the Protect and Preserve International Cultural Property Act requires it. Regarding the authenticity of bronzes buyers have been more and more critical in the past few years, which results in a high number of unsold lots.