Fluorite

Fluorite can display purple, green, blue, yellow and clear zones—sometimes within a single stone. Its geometric crystal structure and layered colors make it especially attractive to people who prefer visible variation.
Contemporary crystal traditions associate fluorite with organization, learning and bringing structure to scattered ideas. It should not be marketed as a treatment for concentration problems or as a guarantee of academic performance. Its value here is visual and symbolic.
Fluorite is considerably softer than quartz, making it vulnerable to scratches, chips and everyday impact. Reserve fluorite rings and bracelets for careful wear, and avoid ultrasonic cleaners. Pendants and earrings generally expose the material to fewer knocks while still showing its distinctive bands.