Super Emeralds

From Sonic Retro

Knuckles got them all!
A Super Emerald

The Super Emeralds are a second set of 7 emeralds found only in Sonic 3 & Knuckles. They are not found in either Sonic 3 or Sonic & Knuckles alone.

To find them, one must enter any Sonic & Knuckles zone with all seven Chaos Emeralds, and jump into a flashing Giant Ring. These transport the character to the Hidden Palace, where the power of the Chaos Emeralds is transferred into large, grey emeralds. He can then jump onto one of the dull grey Super Emeralds and be whisked away yet again into a special stage. The Special Stages are identical to those in Sonic & Knuckles.

In Mushroom Hill Zone, there is one Giant Ring accessible to each character that always leads to a Super Emerald, no matter how many Chaos Emeralds have been collected. Collecting all 7 Super Emeralds unlocks Hyper Sonic, Hyper Knuckles, and Super Tails.

Note that by entering the Hidden Palace, the player loses the ability to transform into the super forms, Super Sonic and Super Knuckles.

The seven Super Emeralds, along with the Master Emerald, in the Emerald Shrine located in Hidden Palace Zone.

Powerful Items in the Sonic the Hedgehog Series
Chaos Emeralds | Super Emeralds | Master Emerald | Time Stones | Chaos Rings | World Rings | Sol Emeralds | Jeweled Scepter | Excalibur