Pearl

Pearls are collectibles that appear throughout Sonic and the Secret Rings and are just as commonplace as rings in the World of the Arabian Nights. They are for charging the Soul Gauge.

Pearl
"Charges up the Soul Gauge."

- Sonic and the Secret Rings manual

Standard pearls that are seen throughout the game. The player can charge up the Soul Gauge by collecting them. However, there are also Skills that, when equipped, allows the player to charge or grant additional energy to the Soul Gauge when certain conditions are met. The amount of energy the Soul Gauge can carry increases as the player grows in level, increasing every five levels. It starts with a capacity of 100 and increases to maximum 300 at about level 50.

Rich Pearl
"20 times greater than a normal pearl."

- Sonic and the Secret Rings manual

Bigger than average pearls and add 20× more to the Soul Gauge. They are more rare to find. They appear larger and have more of a visable aura around them. Their ring counterparts are the Rich Rings.

Trivia

 * Unlike rings, pearls have aunique chime sound that increase in pitch when more pearls are continuously collected, the chimes reset after a short period without collecting pearls.
 * In Sonic and the Black Knight, pearls are replaced with Red Fairies, but during the tutorial stages in Misty Lake you find apples that are lined like pearls and use same chime sound when collected.
 * String of Pearls- An item from Sonic and the Black Knight, collected for the Treasury. It is unrelated to pearls from Sonic and the Secret Rings.