Color:
* Pyrite: Typically a bright, brassy yellow, sometimes with a greenish or iridescent hue.
* Chalcopyrite: Brassy yellow to bronze or even greenish, often with a tarnished surface.
Luster:
* Pyrite: Metallic, often with a bright, almost mirror-like shine.
* Chalcopyrite: Metallic, but often duller than pyrite, with a more subdued shine.
Streak:
* Pyrite: Black, dark gray, or greenish-black.
* Chalcopyrite: Greenish-black to brownish-black.
Hardness:
* Pyrite: 6-6.5 on the Mohs scale (can scratch glass).
* Chalcopyrite: 3.5-4 on the Mohs scale (cannot scratch glass).
Cleavage:
* Pyrite: Cubic cleavage, often with distinct planes.
* Chalcopyrite: Poorly developed cleavage, usually irregular fractures.
Other Distinguishing Features:
* Crystal Habit: Pyrite often forms cubes, octahedrons, or pyritohedrons. Chalcopyrite usually forms irregular masses or tetrahedral crystals.
* Magnetism: Pyrite is weakly magnetic, but chalcopyrite is not.
* Specific Gravity: Pyrite is heavier than chalcopyrite.
In Summary:
* Pyrite is harder, has a brighter luster, and is more likely to have well-defined crystal shapes.
* Chalcopyrite is softer, has a duller luster, and is more likely to occur in irregular masses.
Note: It's important to remember that these are general guidelines, and there can be some overlap in physical characteristics. If you are unsure about a mineral, it's always best to consult with a geologist or mineral specialist.
