Black shiny rock

[Moneybox]

I found a patch of this black shiny rock. It doesn't affect the metal detector and it doesn't attract the magnet. I think it's volcanic glass that's been extruded from the quartz rock.

 

[davent]

View attachment 9887

I found a patch of this black shiny rock. It doesn't affect the metal detector and it doesn't attract the magnet. I think it's volcanic glass that's been extruded from the quartz rock.

Looks like tin mate, but just as bigger average size. Casiterite or something like that.

 

[Moneybox]

Looks like tin mate, but just as bigger average size. Casiterite or something like that.

View attachment 9894

Looks the same but Cassiterite usually registers on the detector?

 

[davent]

Looks the same but Cassiterite usually registers on the detector?

I was in a pit full of the stuff last weekend, no signals at all.

 

[grubstake]

I found a patch of this black shiny rock. It doesn't affect the metal detector and it doesn't attract the magnet. I think it's volcanic glass that's been extruded from the quartz rock.

The black volcanic glass (obsidian) that I've seen, breaks with smooth faces, like actual glass. All of your stuff is textured.

 

[Bushbear]

View attachment 9887

I found a patch of this black shiny rock. It doesn't affect the metal detector and it doesn't attract the magnet. I think it's volcanic glass that's been extruded from the quartz rock.

Looks like coal Is it light in weight?

 

[Imadogman]

Maybe slag. Any old furnaces around the area?

 

[Moneybox]

The black volcanic glass (obsidian) that I've seen, breaks with smooth faces, like actual glass. All of your stuff is textured.

Yes you might be right although this looks like it's been extruded through a gap in the rock rather than broken.

 

[Moneybox]

Maybe slag. Any old furnaces around the area?

Definitely no processing in the area. It's a gold producing area with lots of hollow and burned looking quartz.

 

[Moneybox]

Looks like coal Is it light in weight?

No I don't believe it's coal. It's quite a heavy rock.

 

[Hawkear]

Definitely no processing in the area. It's a gold producing area with lots of hollow and burned looking quartz.

Do any of the quartz pieces laying around have any of the mineral still attached and vice versa which would definitively prove their natural geological association?
Maybe a case for the mineral ID test kit, ie harness, specific gravity, streak colour, fresh fracture type, roast smell, flame colour test etc.

 

[mbasko]

Have you got a ceramic tile or similar about Phil. If so do a streak test on it.
If it's red I'd say you've got some hematite which is common in WA.

Hematite, an iron oxide, is the most common black or brownish-black mineral in sedimentary and low-grade metasedimentary rocks. It varies greatly in form and appearance, but all hematite produces a reddish streak.

 

[Moneybox]

Have you got a ceramic tile or similar about Phil. If so do a streak test on it.
If it's red I'd say you've got some hematite which is common in WA.

View attachment Black rock.MOV

 

[Moneybox]

Do any of the quartz pieces laying around have any of the mineral still attached and vice versa which would definitively prove their natural geological association?
Maybe a case for the mineral ID test kit, ie harness, specific gravity, streak colour, fresh fracture type, roast smell, flame colour test etc.

The rock is wet....

 

[mbasko]

View attachment 9916

Unless my screen is off that looks to be a reddish brown/rust colour that would be expected from hematite (streak is from red to reddish brown).
Example:

Source: Hematite, Hematite streak https://geology.com/minerals/hematite.shtml

P.s. hematite is also non magnetic or very weakly magnetic so that fits too along with it being quite heavy.