Hi! My name is ***** ***** I would be happy to help with your beautiful lamp.
With its distinctive lion mask on one side and the face of a maiden (possibly the goddess Diana the huntress) on the other side and "dolphins" holding laurel wreathes in their mouths as faux handles, mounted on an alabaster socle and wooden base, this piece is Italian and dates to the 1910s or 1920s.
If you were to see it for sale in an antique store, it would have a full retail value of $400.
This is also the replacement value for insurance purposes.
Expect to get 30% - 40% of this if you were to sell at auction or on line (eBay etc).
I do hope this helps!
Please let me know if I can be of further assistance with this, I would be glad to.