A Pearl Tear is the ultimate source of a Mermaid Princess' power. The Pearl Tears of the seven Princesses are
what Gaito and his minions are after, because they possess the power to sumon Aqua Regina. They're the pearls that the Mermaid Princesses keep in their Shell Lockets. Truthfully, the lockets hold no power whatsoever and it is actually the pearls that are powerful.
- A Pearl Tear allows the Mermaid Princess of its possession to transform into her Idol Form. In the very first episode of season 1, when Kaito throws his pendant to Lucia, her pearl suddenly turns into an E-pitch microphone for the first time.
- A Mermaid Princess cannot sing well without a Pearl Tear. (With the exception of Sara,or mermaid princesses that can already sing well)
- It enables a Mermaid Princess to have her Coming of Age Ceremony, as it is connected to Aqua Regina.
- A Pearl Tear has the power to heal someone, as Lucia's did when Kaito nearly drowned.
- A Pearl Tear's shine can blind or harm a villain temporarily, just like how Karen's did in Episode 27, so that Lucia, Hanon, and Rina could escape the Black Beauty Sisters. Another example is Hanon when Yuri tore Mitsuki's sheet music in Episode 9.
- Coco and Noel's pearls have been used by Sheshe and Mimi in Episode 49 for them to sing more powerfully. In the second season, they were granted power which let them sing just as powerfully without a pearl to empower them.