Does anyone which stone is this

[Yokietoks]

Hi ya
My sister has this stone but not sure what it is. Does anyone have any idea?

 

[fredflintstone]

I would say, calcite.

 

[Nick_G]

Yes it looks like calcite. The dark grey metallic-looking crystals maybe galena.

 

[fredflintstone]

Yes it looks like calcite. The dark grey metallic-looking crystals maybe galena.

Yes, I think you're right. All on limestone.

 

[Yokietoks]

Thank you, I was thinking it to be quartz but could be calcite. Is it not quartz?

 

[fredflintstone]

Thank you, I was thinking it to be quartz but could be calcite. Is it not quartz?

No, not quartz. The crystal habit. The luster. The crumbling (damage) of the crystals all scream calcite. Calcite is 3 hardness on the mohs scale. A finernail is 2 1/2. Quartz is 7. Nice though.

 

[fredflintstone]

Oh, as another person mentioned. Looks like you have galena on the crystal. That is lead. A lead crystal.

 

[Nick_G]

Oh, as another person mentioned. Looks like you have galena on the crystal. That is lead. A lead crystal.

Well galena is lead sulphide, PbS. It's the main ore of lead though.

The matrix is showing the typical calcite cleavage, which is the property of splitting preferentially in certain directions. With calcite, a sharp blow splits it into rhombohedrons, like the outline of your specimen. Quartz doesn't have any cleavage, and it's much harder (7 on Moh's scale).

Try a drop of vinegar on the creamy white areas. If it fizzes, you've got calcite.

 

[Yokietoks]

Okay so most votes go to calcite. And I see it has been deeply spec’d in the above post. Good knowledge. I will try the vinegar test

 

[fredflintstone]

Well galena is lead sulphide, PbS. It's the main ore of lead though.

The matrix is showing the typical calcite cleavage, which is the property of splitting preferentially in certain directions. With calcite, a sharp blow splits it into rhombohedrons, like the outline of your specimen. Quartz doesn't have any cleavage, and it's much harder (7 on Moh's scale).

Try a drop of vinegar on the creamy white areas. If it fizzes, you've got calcite.

Yes. It is.