Weight of aluminum

I have two aluminum pans that weigh weirdly. I have a Cook's Essentials 9.5 inch hard anodized frying pan that's approximately 3.5mm thick and somehow it weighs the same as my All-Clad 10.2 inch hard anodized frying pan that looks about 4mm thick. I'm assuming that different alloys affect the weight of the cookware. Now I don't have a kitchen scale, but just picking up the pans there's very little noticeable difference in weight. I expected the All-Clad pan to weigh more due to size and thickness.