This is an exceptionally rare Tiffany Studios oil lamp that was later converted to electricity. The bronze lamp parts are marked, 'Tiffany Studios' (see picture), while the two glass pieces are unmarked. Most likely, the following is the evolution of the lamp: It was initially an oil lamp. When electricity came into usage in the US towards the first part of the twentieth century, the owner of the lamp sent the lamp to Tiffany glassworks (called, 'Tiffany Corona' then) to have the lamp converted to electricity. The Tiffany factory then either fitted the lamp with two glass pieces at their own factory, or had the glass pieces made by the Loetz factory and had them fitted at their own factory (since perhaps many people were getting their oil lamp converted to electricity, Tiffany might have had such a working relationship with Loetz). Please refer to pages 137, 138 and 139 of Ricke's book, 'Loetz Bohemian Glass 1880-1940', for three 'pulled-feather' examples of Loetz articles done in 'Phanomen in Tiffany art'. The 'Pulled-feather' decor in the two glass pieces of the lamp is reminiscent of the work of Franz Hofstotter of Loetz and might also explain why the glass pieces on this lamp are not signed (typically, Loetz did not sign most of their pieces). The two glass pieces fit so well with the bronze wicker-adjuster housing of the lamp, it would be hard to explain it if the conversion was not done at the Tiffany factory. The lamp is 18 inches (46 cm) tall and 9 inches (23 cm) wide at the widest. Except for a few expected rim-chips on the top glass piece (the chips are hidden when that glass piece sits on the bronze holder), the lamp is in good condition.
N.B. Because of the high value of the lamp, payment with check, money order or wire transfer would be preferred.