Physical and Chemical properties that make diamonds ideal for drillbits

Physical:

• It is a poly-morph of the element carbon
• Is a ten on the hardness scale
• Hardest substance known to man; highest hardest so great for cutting things (like for drill bits)
• Near impossible to be scratched
• Difficult to break
• Can last for millenniums ("forever")
• Stiff
• Very effective abrasives

Chemical:

• Isn't compressible
• Has a low thermal expansion