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.
