Here's what that means:

* Octahedral: This refers to the shape of the cleavage planes. An octahedron has eight triangular faces.

* Perfect: Fluorite breaks very cleanly along these planes, producing smooth, flat surfaces.

Visualizing Octahedral Cleavage:

Imagine a cube with its corners cut off to form eight triangular faces. Fluorite will cleave along these triangular planes.

Let me know if you'd like me to explain more about cleavage in minerals!