* It splits easily along specific planes of weakness. For muscovite, this is along its sheet-like structure.
* It's highly likely to break into thin, flat pieces. This is why muscovite is sometimes used in makeup, as a glitter component.
Tenacity itself describes a mineral's resistance to breaking or deforming under stress. Common tenacity descriptions include:
* Brittle: Breaks easily with little to no bending (like quartz)
* Malleable: Can be hammered into thin sheets (like gold)
* Ductile: Can be drawn into wires (like copper)
* Sectile: Can be cut with a knife (like talc)
* Flexible: Can be bent but doesn't return to its original shape (like mica)
* Elastic: Can be bent and returns to its original shape (like rubber)
While muscovite is flexible, it's more specifically described by its perfect basal cleavage, emphasizing its tendency to split into thin sheets rather than describing its overall resistance to breakage.
