With a thin coating of "stuff" that peels off like metallic foil. Iron oxide spiced with rare earths I think it usually is. The pics in this article illustrate

With a thin coating of "stuff" that peels off like metallic foil. Iron oxide spiced with rare earths I think it usually is. The pics in this article illustrate it: https://www.extremetech.com/computing/326292-why-lying-about-storage-products-is-bad-an-ibm-deskstar-story https://www.extremetech.com/computing/326292-why-lying-about...