B&P Lamp 7" Student Shade, Tam, Opal, Hobnail, Crimp Top This opal, or white milk glass, shade has an embossed hobnail pattern with a "crimp top" It has a 7" fitter, an 8 1/8" overall bulge, and stands 6" tall This shade is hand-blown here in the United States using the same technique that has been around for over a century