An unknown mineral possesses a black streak and a density of 18g/cm^3. Base on this data can you tell what mineral is it? Do you think it is metallic or non-metallic?
Answers
Answer:
Picture this: most rocks on Earth’s Crust have a density that is around 3 g/cm3. Porous sedimentary and igneous rocks tend to have lower densities than that, while some metamorphic rocks are compact. A piece of rock made from a large proportion of a transition metal oxide (say, FeO or Fe2O3) can be denser than average. Sulfides like cinnabar and galena can be quite a bit denser than most rocks (because they contain mercury and lead, respectively). But you don’t tend to find sulfides at the surface; they are typically found in mines.
Rocks generally do not reach densities as high as 18 g/cm3. The density you report is very close to that of tungsten, which is just over 19.3 g/cm3. You might have a piece of tungsten in your hands. Perhaps it is anodized and that is why it looks like that.
Perhaps, what you have is a lump of gold/silver alloy and it has tarnished. The densities of gold and tungsten are nearly identical. But if it is being alloyed with small amounts of silver its density will decrease.
most rocks on Earth’s Crust have a density that is around 3 g/cm3. Porous sedimentary and igneous rocks tend to have lower densities than that, while some metamorphic rocks are compact. A piece of rock made from a large proportion of a transition metal oxide (say, FeO or Fe2O3) can be denser than average. Sulfides like cinnabar and galena can be quite a bit denser than most rocks (because they contain mercury and lead, respectively). But you don’t tend to find sulfides at the surface; they are typically found in mines.
Rocks generally do not reach densities as high as 18 g/cm3. The density you report is very close to that of tungsten, which is just over 19.3 g/cm3. You might have a piece of tungsten in your hands. Perhaps it is anodized and that is why it looks like that.
Perhaps, what you have is a lump of gold/silver alloy and it has tarnished. The densities of gold and tungsten are nearly identical. But if it is being alloyed with small amounts of silver its density will decrease.