[ginko]

So is this actually metallic nickel or just nickel ions?

[Engineering-MD]

It’s not clear but I would hazard that it’s ions, as it would likely precipitate out of suspension otherwise. Also, as an ion it’s more likely to have a biological effect.

[jmmcd]

The ground ends up purified (somewhat) either way, I guess. If we want to use the nickel, will it make a big difference?

[AllegedAlec]

Ions, given the colour. Metallic nickel is silvery, but Nickel II and III are greenish and greenish blue respectively.