The Red Pearl is a treasure from a fictional Greek Legend in the Cutie Honey anime. It is said that a mermaid is able to create one by crying tears and are extremely valuable.
The mermaid Chiruru after being captured begged to be released making her shed a tear which later turned into a red pearl. She was later beaten by the fisherman to shed more tears but she died from the beatings with no more tears shed. This caused Chiruru's sister Marara to become Sea Panther and take revenge on humanity.