[taNk (OP)]

Hello!

I was out tracking down some minerals to my collection and stumbled on two which i can't identify.


Pic nr1:

I think it looks like an Amphibole with its texture, it leaves no mark on porcelain or if it does it's white-ish colored.
it's not heavy at all, estimated 3-4
Luster i'd say glass
If it's not an Amphibole it might be Sphalerite ((Zn,Fe)S), atleast that is all i can think of. What do you think?

Pic nr2:

I'm 90% sure it's Galena (PbS), it leaves a black-dark blue streak as the picture shows on porcelain. It's kinda heavy maybe 7-ish (If so then it must be Galena).
But i'm having a hard time seeing the cube shapes and that is why i'm not sure. I found it in an area where Azurite were to be found. What do you think?

[JimBob]

Bass?

I study mud - sedimentary rocks

[taNk (OP)]

Bass?

Sorry, what do you mean?

[Bass]

He was referring to the other resident curmudgeon on the Geology forum here- JimBob is just a big softie.

It's always hard to tell minerals from photos alone.

Photo 1: Can you scratch this mineral with a knife? It looks somewhat fibrous- and may be amphibole (which covers a range of minerals). Is cleavage better developed in one direction, or is it more equal in 2 directions? It's not sphalerite.

Photo 2: How soft is the gray mineral? Galena is fairly soft. Galena sometimes can be massive (too fine to see individual crystals). Can you see any crystals if you use a hand lens or microscope? Another possibility is chalcocite or digenite if you found it in an area with azurite. Can you describe the place you collected the mineral? an old mine? How much azurite was present? Malachite (green copper mineral)? Turquoise? Quartz?

[taNk (OP)]

He was referring to the other resident curmudgeon on the Geology forum here- JimBob is just a big softie.

It's always hard to tell minerals from photos alone.

Photo 1: Can you scratch this mineral with a knife? It looks somewhat fibrous- and may be amphibole (which covers a range of minerals). Is cleavage better developed in one direction, or is it more equal in 2 directions? It's not sphalerite.

Photo 2: How soft is the gray mineral? Galena is fairly soft. Galena sometimes can be massive (too fine to see individual crystals). Can you see any crystals if you use a hand lens or microscope? Another possibility is chalcocite or digenite if you found it in an area with azurite. Can you describe the place you collected the mineral? an old mine? How much azurite was present? Malachite (green copper mineral)? Turquoise? Quartz?

I see haha!

Photo 1: I'm not sure about the cleavage, i think in one direction only using my hand lens. And the knife scratches it. (Correct me if i'm wrong but doesn't a knife on mohs scale represent 5?)

Photo 2: It is very soft, can easily scratch it with a knife. "Galena sometimes can be massive (too fine to see individual crystals)."  I see, that is maybe why i cant see any ideal cube shaped crystals with my hand lens.
The place is one of Swedens oldest silver mines (Stollbergs gruvan) where they later change from silver to iron, lead, zinc and manganese.
It said that Azurite were to be found there but didn't found any, so i guess not much was present. I did not see any Malachite or Turquoise but alot of Quartz ( found a rock with alot of 2 centimeter long perfectly hexagon shaped Amethyst crystals, which looks great on my bookshelf at home now! haha. )

Chalcocite is not a very common mineral in Sweden as far as i know but when i read about it and compare them i can see a resemblance. How do you seperate Galena from Chalcocite if you don't see the crystal shapes on Galena? I mean both have metallic reflections and they are pretty heavy and soft.

As a second year mining engineering student from Sweden i just want to thank you for the respons and say that this site is a gold mine.

[Bass]

Galena it is then!

[chris]

You guys are amazing!