I could not find any Tiffany stamp on it. It was probably on the missing base plate. I do know how long it has been in the family, it is extremely heavy. The shade is unusual in that it has the 3 1/2 inch opening that allows you to actually place the shade over the ornate fennel on top.

The lamp is for sale if the value is right.

Thanks, Sandy, for your response. The shade would have been signed as well as the base if this were Tiffany so even without the base plate I can pretty confidently say that this is not Tiffany.
Based on the photos and information provided, and subject to examination, this is:

An American Art Deco Tiffany style slag glass and brass lighthouse table lamp
unattributed maker, early 20th Century
With an eight-sectioned domed shade with pierced stylized foliate ribs and rim, flaring columnar pillar with slag glass body and pierced brass frame, on a circular foot.
24 1/2 inches tall overall; diameter of shade 19 inches
CONDITION: lacking base plate; break to one shade panel, one socket replaced.
PROVENANCE: inherited; descended in the family
$300-500*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, and thank you for using Mearto.

Thank you so much! This was very helpful.