Chromite vs Magnetite
Chromite and Magnetite are commonly confused, and 4 measured properties separate them — density most clearly.
Chromite vs Magnetite
Chromite
FeCr2O4
Iron chromium oxide — the only ore of chromium there is, and therefore the mineral every stainless steel depends on.
Magnetite
Fe3O4
The most magnetic naturally occurring mineral, a major iron ore, and the reason the compass exists.
| Property | Chromite | Magnetite |
|---|---|---|
| Cleavage Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | none; parts along octahedral planes |
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | cubic | cubic |
| Density | 4.5–4.8 g/cm³ | 5.15–5.2 g/cm³ higher |
| Lustre Categorical values can be listed side by side but not ordered or subtracted. | metallic to submetallic | metallic |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 5.5 | 5.5–6.5 higher |
| Streak Categorical values can be listed side by side but not ordered or subtracted. | dark brown | black |
Why these get confused
both black and submetallic; chromite's streak is dark brown against magnetite's black, and it is far less magnetic
The confusion is a real and documented one, not a resemblance we have invented.