I… yeah.
New one on me. These are likely a variant of the ‘open smile phosphate’ balls, but these are a little more insidious as they’re not quite as obviously fake.
These tend to be stuck on an actual real matrix – one or two of the pieces I saw seemed to be on a variscite matrix which would be worth a fair few quid just on its own!
They’re using the name of a real mineral – cobaltite, which is an ore of cobalt and occurs typically in a gunmetal, black, or reddish silver colour – it is also toxic, being CoAsS – a cobalt arsenic sulphate.