[jimbobthrowawy]

I think the cards are mostly plastic by mass, and the silicon is doped with other elements. (mostly lighter, some heavier. IIRC)

The actual metal storing magnetic charge in a hard drive is tiny also, with some drive platters being mostly ceramic. Regardless, if you were to personify the force of entropy, it would be greatly angered by humanity and modern computing.

[KeplerBoy]

Sure. I completely agree. Also micro sd cards are certainly not optimized for weight and I wouldn't be surprised if I made a mistake in my "calculation".