Pyrrhotite
| Colour | Brown, Gold |
|---|---|
| Mohs hardness | 3.5 – 4.5 |
| Lustre | Metallic |
| Streak | Dark grey – black |
| Crystal system | Monoclinic, with hexagonal polytypes |
| Cleavage | Absent |
| Fracture | Uneven |
| Chemical formula | Fe 1−x S (x = 0 to 0.125) |
| Specific gravity | 4.58 – 4.65, average = 4.61 |
What is Pyrrhotite?
Pyrrhotite is an iron sulfide mineral with the formula Fe(1−x)S. It is an iron-deficient nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is weakly magnetic. The magnetism decreases as the iron content increases, and troilite is non-magnetic. Pyrrhotite is generally tabular and brassy/bronze in color with a metallic luster. The mineral occurs with mafic igneous rocks like norites, and may form from pyrite during metamorphic processes. Pyrrhotite is associated and mined with other sulfide mi
How to identify Pyrrhotite
- Lustre: Metallic.
- Hardness: Mohs 3.5 – 4.5 — soft; a knife will scratch it.
- Streak: Dark grey – black.
- Habit: Monoclinic, with hexagonal polytypes crystal system.
Pyrrhotite in different forms
Stones often confused with Pyrrhotite
Frequently asked questions
How hard is Pyrrhotite?
Pyrrhotite is Mohs 3.5 – 4.5 on the hardness scale.
What colour is Pyrrhotite?
Pyrrhotite is typically brown, gold (Bronze, dark brown).