[DylanK25]

Hey so very recently (just a couple days ago) I officially began collecting elements. My dad gave me some Cobalt that he had in college. It's abour 25 years old and is a bluish colored grainy shiny mass. I was wondering if this is pure cobalt or is it some sort of alloy or combination, since most cobalt is silverish gray. Anyone know the answer to this if so thanks! 😀

[Hunter2]

If it is so old, it can be oxidized. Without an analysis its difficult to say.

[Borek]

Note: oxide layer is just on the surface, bulk of the sample is what it originally was.

[Enthalpy]

Pure cobalt is just grey.

[nicamarvin]

I am also collecting Cobalt, but for electroplating instead of collecting, it is very difficult to find Cobalt per pound at the market price, people that sell it are over charging way too much, so I buy cobalt carbonate and take it from there, one way to distinguish from Cobalt from Nickel(both are very alike) aside from the color difference that some people may have trouble picking up, is that Cobalt will form a flash coat of copper when in contact with copper sulfate solution, I have done the experiment myself, this is also found on old books of electroplating cobalt.

[shiffdaddy]

If its magnetic it must contain some level of either iron, nickel, or cobalt and front there you could try testing in like HCl (turns the acid a pink color and purple on heating) and in Nitric acid cobalt slowly forms a red solution of cobalt nitrate.  This would confirm the presence of cobalt but no exact purity, just confirmation of the presence of Cobalt

Ben

[nicamarvin]

Yes, I forgot about that too, Nickel chloride/sulfate compounds are green looking while cobalt is more like purple-magenta.

[Enthalpy]

If its magnetic it must contain some level of either iron, nickel, or cobalt

Ferromagnetism is a molecular property, not an atomic one. Among other examples, austenitic stainless steel isn't ferromagnetic, while CrO₂ makes permanent magnets. In addition, normal metallic gadolinium too is ferromagnetic.

[shiffdaddy]

Interesting, yeah I guess my statement was very simple and incorrect.