Bismuthinite vs Stibnite
Bismuthinite and Stibnite are commonly confused, and 1 measured property separates them — density most clearly.
Bismuthinite vs Stibnite
Bismuthinite
Bi2S3
Bismuth sulfide — the ore of the heaviest element that is, for practical purposes, not poisonous.
Stibnite
Sb2S3
Antimony sulfide, in soft steel-grey blades — the ore of antimony, and the kohl of the ancient world.
| Property | Bismuthinite | Stibnite |
|---|---|---|
| Cleavage Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | perfect in one direction |
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | orthorhombic | orthorhombic |
| Density | 6.7–6.9 g/cm³ higher | 4.6–4.7 g/cm³ |
| Lustre Categorical values can be listed side by side but not ordered or subtracted. | metallic | metallic |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 2 | 2 |
| Streak Categorical values can be listed side by side but not ordered or subtracted. | lead grey | lead grey |
Why these get confused
both soft, bladed and lead-grey; bismuthinite is markedly denser
The confusion is a real and documented one, not a resemblance we have invented.