Natural Pyrite Crystals
The brassy-yellow colour of pyrite gives it a gold-like appearance.
Although pyrite is much harder than gold, it's also more brittle. Strike a piece of gold repeatedly and it will become flatter and flatter. Strike pyrite in the same way, and it will shatter into pieces.
Pyrite is a naturally occurring mineral with a crystalline structure. Crystals can form in various shapes, one of the most common being a cube.
Isometric or cube-shaped crystals are one of the simplest and most common shapes in minerals.