What is more useful when it is broken?

Riddle: What is more useful when it is broken?

Answer: An egg..

Riddle: What is more useful when it is broken?

Hint: Breakfast begins after the crack.

Why this answer works
An intact egg isn’t very useful for eating—its usefulness starts once you crack (break) it to cook.

Fun fact
Most store-bought chicken eggs are unfertilized; the shell is ~95% calcium carbonate and protects the porous membrane inside.

Popular variations
Break it to make it? → Egg
Useful only after a crack? → Egg

Related riddles
What has to be cracked, made, and told? → A joke
What has a heart that doesn’t beat? → An artichoke

FAQ
Is “glow stick” valid?
Clever, but the classic answer is “egg.”
Why not “record”?
Breaking a record is good, but that’s figurative; the riddle points to a literal object you physically break.