As many of you may know, I collect minerals. Recently, I bought a book that describes mineral tests with Cobalt Nitrate. Any ideas of how I could make it?

I think cobalt nitrate is made like every other nitrate, mix nitric acid with the elemental metal or carbonate, hydroxide, oxide compounds.

 

i think razor blade is made from cobalt, drop it in to nitric acid see what happens

 

 

(cobalt salts r carcinogen)

Go out to a pottery/ceramics shop and try to obtain some cobalt carbonate, and dissolve that in dilute nitric acid, as [w00t] suggested. Many pottery shops also have cobalt sulfate, which is a soluble cobalt salt and I'm quite sure that is as useful as cobalt nitrate, but much easier on storage (it is not hygroscopic).

 

Do not use the cobaltosic oxide from pottery stores, Co3O4. This stuff is remarkably inert. I have some, but I could not dissolve it in any acid I have, not even boiling hydrochloric acid, with a reductor present in order to convert the cobalt (III) in the cobaltosic oxide to cobalt (II). The carbonate, however, with the help of some moderate heating, nicely dissolves in dilute mineral acid.