Hematite vs Magnetite
Hematite and Magnetite are commonly confused, and 5 measured properties separate them — crystal system most clearly.
Hematite vs Magnetite
Hematite
Fe2O3
Iron oxide — the most important ore of iron, and the red pigment used since the Palaeolithic.
Magnetite
Fe3O4
The most magnetic naturally occurring mineral, a major iron ore, and the reason the compass exists.
| Property | Hematite | 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. | trigonal | cubic |
| Density | 5.26–5.3 g/cm³ higher | 5.15–5.2 g/cm³ |
| Lustre Categorical values can be listed side by side but not ordered or subtracted. | metallic to earthy | metallic |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 5–6 | 5.5–6.5 higher |
| Streak Categorical values can be listed side by side but not ordered or subtracted. | red to reddish brown | black |
Choosing between them
Magnetite is recorded as a substitute for Hematite — cheaper.
What it gives up: Lower grade, so it must be concentrated before smelting — magnetically, which is cheap, but it is a step hematite skips.
In this application, on the evidence cited above.
Why these get confused
separated by the streak test: black versus red-brown
The confusion is a real and documented one, not a resemblance we have invented.