It is about the size of your small fingers nail. It does not detract from the lamp at all. You can see it in the photos.
In the photos you can see dirt from years of attic storage but it will wash right up. It has a beautiful old mold mark running across the base. It's a sign of age and also. You can see that the filler cap sits at an angle rather than flat like the newer reproductions. The bottom edge turns into a nice amberina glass color. The item "Vintage Red Lincoln Drape Aladdin Lamp Tall 1939 Old One" is in sale since Thursday, October 21, 2021. This item is in the category "Collectibles\Lamps, Lighting\Lamps". The seller is "primepicks46" and is located in Remsen, Iowa. This item can be shipped to United States.