Under pressure is the only way I work, and by myself is the only way I am hurt. What am I?
Common Wrong Answers
“Coal”
While coal is related to diamonds in the carbon family and forms under pressure, it does not fit the criteria of being hurt when alone, as it can exist without being harmed.
“A balloon”
A balloon does rely on air pressure to function, but it can be harmed or popped whether alone or in a group, which contradicts the riddle's conditions.
“A pressure cooker”
A pressure cooker operates under pressure, but it does not get 'hurt' by being alone; it simply won't function without heat and contents.
Similar Riddles
Precious stones in a pack of cards
Though liquid in nature, don't push me too far for then I will break, and the damage may scar. What am I?
If you break me I do not stop working, If you touch me I may be snared, If you lose me Nothing will matter.
What gets broken without being held?