The FYI might be poor phrasing, but GP is right that many people confuse the two. This isn't helped by many sellers of novelty "tungsten" online selling tungsten carbide and mentioning it in the fine print, if at all.
If anyone knows where to get a tungsten cube I would be interested. I’ve wanted one since reading this post a few years ago but every vendor usually sells alloys.
This vendor sells cubes of various sizes that they claim to be 99.95% tungsten - https://luciteria.com/metal-cubes/tungsten-cube. I have one of the 1cc cubes and it seems to be of good quality. They also sell a lot of other exotic elements.
Perfect, thank you! Looking it seems they both have a kilo of pure tungsten in cube form measuring 38.1mm^3 or a kilo of tungsten carbide measuring 40mm^3.
I honestly wouldn't have noticed that the Midwest Tungsten Service products weren't pure tungsten, but when I went back to the amazon page, I found a note from the seller:
>The tungsten sphere is 90% tungsten with nickel/iron for the remainder, the aluminum sphere is 6061 alloy.
This actually seems to apply to most of their products. Not just the spheres.
If you search Amazon for "pure tungsten", you'll find vendors selling cubes that are at least more pure than this vendor's stuff. There are also other items that claim to be high purity tungsten.
Can't blame them for selling alloy. Pure tungsten is extremely brittle and virtually unmachineable. So they'll sell you nickel alloy, because you can work that to tolerance. No powder metallurgy required.
But I do appreciate your story about tungsten carbide, too :-)