Mystery mineral

[Edge 524]

I believe I picked this up in the Belmont mtns.

Very heavy, black streak test, not in the least bit attracted to a magnet. I took a grinder to it which did little but polish a bit. No sparks, didn't fracture or leave dust.

Not ilmenite, magnitite or graphite.

Probably something obvious designed to trip me up.

above is where I used the grinding wheel.

[Sonoran Dave 2,070]

I'm guessing a variety of copper sulphide. Maybe chalcocite, or even covellite. I have a chunk of covellite here, that is so dark indigo... it's almost black. Since the picture makes it look grey, I'd lean towards chalcocite.

[Edge 524]

4 hours ago, ArcticDave said:

I'm guessing a variety of copper sulphide. Maybe chalcocite, or even covellite. I have a chunk of covellite here, that is so dark indigo... it's almost black. Since the picture makes it look grey, I'd lean towards chalcocite.

Covellite leaves a grey streak though. Going with chalcocite. Now, where's my acids, hmmm

[Bob(AK) 53]

How hard is this piece? Both chalcocite and covellite are quite soft and both will ring loudly on a detector. The top photo

looks brown on the end is that so?

[Edge 524]

It's very hard, not black but gives off an interesting silver/ blueish metallic hue. 

I read chalcocite is mildly magnetic when heated. ..hmmm