Cold water agates are a different breed. These form in limestone and they have a special name because they are thought to form in a special way (we’ll talk about that in a moment). These form in limestone and are almost always completely colorless, composed of clear and milky white bands. They’re found abundantly in Southern Michigan where limestone is common and they’re often quite small. While lacking the bold colors of their northern cousins, they can still be remarkably beautiful.
Beyond that, as far as this geologist is concerned, you can call your agate variety whatever you like. There’s no commission or organization for that, it’s simply about what names catch on and which ones don’t. I even named my own agate variety: the Elvis Agate.
Aside: The Elvis Agate is named in honor of Dr. Jackie Huntoon, who once explained that she named a sedimentary unit in Utah “the Elvis Formation.” This was not long after the death of Elvis and at a time when there were Elvis “sightings” every day in the tabloids and all sorts of conspiracies. She and a colleague were working and noticed a small and rather insignificant rock unit that had never been described at a location. And then they noticed it at another spot… and another. Suddenly, they realized that this layer of rock wasn’t just in one spot, it was everywhere and it became a running joke with them: the more you want to see it and the more you look for it, the more you see it. Like sightings of Elvis. So as a joke, they named it the Elvis Formation and submitted it to the humorless USGS for inevitable rejection… but the USGS had just taken huge funding cuts and the few employees left apparently didn’t care anymore. And so the Elvis Formation got its name; the more you want to see it, the more you see it wherever you go!
The Elvis Agate is inspired by that story. It’s a fun label to apply to pieces folks show you. Is this an agate? If you squint your eyes real hard and look at it from this angle under this particular light, you can kind of see it… That’s an Elvis Agate. It’s a piece where you can only see that it’s an agate if you really really want it to be an agate!