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Early 20th c. white metal slag glass lamp. I'd say the base is not original to the shade-varying styles.
The lamp and the shade don't go together. The base is circa 1960s, wire too. Socket with switch looks newer, 1990s. Shade is "slag glass" with pierced metal, circa 1900 to 2020.
Tiffany shades are marked on the glass outside and embossed on the metal rim inside.