Verdigris is that weird green stuff you sometimes see on old copper or bronze coins. It can range from a faint, minty haze to thick, crusty blobs that look like the coin was stored in a compost pile. And while it might look kind of cool in certain lighting, it’s not a sign of anything…

If you’ve ever submitted a coin for grading and gotten the dreaded Environmental Damage tag back from PCGS, you know how frustrating it can be. Unlike more specific designations like “Cleaned” or “Scratched,” this one feels like a catch-all, but there’s a little more to it than that. This post breaks down exactly what PCGS…

You’ll see both of these terms tossed around a lot in coin collecting, especially when it comes to details grades, and sometimes they’re used interchangeably. But while they overlap, they’re not identical. Think of it like this: all corrosion is environmental damage, but not all environmental damage is corrosion. In this post, we’ll clear up…

The phrase “shipwreck coin” carries a certain mystique. It conjures images of buried treasure, sunken galleons, and ocean-crusted riches pulled from the deep. But what does that actually mean for a coin’s condition? This post strips away the romance and looks at the science. We’ll break down what shipwreck corrosion really is, how it affects…

Not all corrosion looks the same. Sometimes it’s a faint green haze creeping along the edges. Other times it’s a thick, black crust that seems to rise up out of the metal itself. Each color tells a different story, about what the coin has been through, what environment it’s been exposed to, and what kind…

Corrosion is one of the most destructive forms of damage a coin can suffer. It eats away at the surface, breaks down metal at a chemical level, and leaves behind pits, discoloration, or flaky crust that can make a coin nearly unrecognizable. Most of the time, corrosion happens when a coin is exposed to moisture,…