the ultra-rare collectible would become the most valuable American postage stamp to date. So, what makes the "Z" Grill lot so special? After the Civil War, stamps were still relatively new ...
A rare Benjamin Franklin Z-grill stamp from 1868 could fetch as much as $5 million once it hits auction in New York. There are only two known stamps in existence.
A famous invert error stamp has sold for well over its estimate at a New York sale. Discover the upside-down 1c Pan-American ...