Sol Emerald

The Sol Emeralds (ソルエメラルド Soru Emerarudo) is a set of seven emeralds of great power that originates from another dimension. Just like their inter-dimensional counterpart, the Chaos Emeralds, they are usually the sought out by heroes and villains alike due to the great power they possess. They appear in Sonic Rush, as well as in its sequel Sonic Rush Adventure, where they are guarded by Blaze the Cat. They are cube and not octogon like the Chaos Emeralds,.

Powers and Traits
The Sol Emeralds shares many similar traits with the Chaos Emeralds, but they are rectangular in shape (emerald cut) unlike the pointed shape (brilliant cut) of the Chaos Emeralds. Each Sol Emerald possesses unlimited amounts of great power similar to that of Chaos Energy (dubbed Sol Energy by fans), and it can be harnessed to empower machinery and creatures alike. Also, if a person harnesses the power of all seven Sol Emeralds, they can be used to achieve a super transformation (Burning Blaze in Blaze's case). Their powers and theme appear to revolve around fire.

Another thing the Sol Emeralds have in common with the Chaos Emeralds is apparently their ability to convert thoughts into power, although it is unknown to what extent. This allowed Blaze to restore the Emeralds' power after they were drained by Dr. Eggman and Eggman Nega. Also, just like the Chaos Emeralds, if the Sol Emeralds are drained of their power, they will become powerless and look like normal stones.

It is also interesting to note that they possess magnetic properties, another trait they share with the Chaos Emeralds; Both Dr. Eggman and Eggman Nega quote that the Chaos and Sol Emeralds are connected like the north and south pole of a magnet and can therefore attract and repel each other, and can react in each other's presence, and, if in the wrong hands, their power could destroy the world. It is currently unknown if the Sol Emeralds has an equivalent to the Master Emerald that can control the Sol Emeralds.

The Sol Emeralds shares a deep and important connection to Blaze's world and can seemingly draw her world to them, should the emeralds leave their world.

Role in the games
The Sol Emeralds shares a similar role with the Chaos Emeralds in the modern games, as serving as necessary plot devises in order for the game's story to progress.

In Sonic Rush, the Sol Emeralds are not collected from Special Stages like the Chaos Emeralds, but are collected after each boss fight where Blaze grabs one from Dr. Eggman. In the story they were under the protection of Blaze the Cat for an unknown amount of time, until Dr. Eggman came to Blaze's world and stole them. Blaze, however, follows Dr. Eggman into Sonic's world and with the help of Cream the Rabbit, she retrieves them one-by-one from Dr. Eggman. In the Final Story of Sonic Rush, Blaze is assaulted by Dr. Eggman and Eggman Nega in their Egg Salamander and they drain the Sol Emeralds of their power. As Sonic comes to her rescue and the Eggmen leaves, Blaze is left discouraged due to the Sol Emeralds powerless state, but thanks to the encouragement from Sonic and his friends, Blaze re-energizes them and uses their power for the first time to become Burning Blaze. She then joins up with Super Sonic and defeats the Egg Salamander, and then returns to her world with the Sol Emeralds.

The Sol Emeralds returns in the sequel Sonic Rush Adventure. Like the Chaos Emeralds, the Sol Emeralds have to be collected to progress the story, but unlike the Chaos Emeralds which are gained from a race with Johnny, the player gets a Sol Emerald after clearing a specific mission. These missions can be obtained from Gardon, but to obtain them all, the player must have unlocked and beaten Hidden Islands 6, 8 and 12. They do not play a role in the story, until near the end of the story where Blaze uses them to become Burning Blaze, while Sonic uses the Chaos Emeralds to become Super Sonic, in order to combat the Egg Wizard. Tails then later uses the power from both sets of Emeralds to create a vessel that can bring both him and Sonic back to their own world.

Sol Emeralds in other media
The Sol Emeralds appears in Archie's Sonic the Hedgehog and serves as the Sol Zone's equivalent to the Chaos Emeralds of Mobius Prime (Sonic the Hedgehog's home dimension). These versions of the Sol Emeralds holds a very important role in maintaining the Sol Zone, and the Zone itself will grow unstable if they are missing from it. Their theme around fire is also more prominent in this media, as a Sol Emerald directly bursted into flames when Shadow tried to use Chaos Control with one of them. Just like in the games, they are guarded by Blaze the Cat.

At some point in time, the Sol Emeralds disappeared and Blaze immediately began her quest to find them or risk the end of her world. After encountering Sonic the Hedgehog, Miles "Tails" Prower, who had arrived in the Sol Zone and Marine the Raccoon, Blaze was given Mobius Prime's green Chaos Emerald by Sonic after they had retrieved it from Johnny, Captain Whisker and Dr. Nega, so it could help her locate the Sol Emeralds. With the Chaos Emerald's help Blaze managed to locate some of the Sol Emeralds, before she passed it on to Shadow the Hedgehog, stating she could find the remaining Sol Emeralds with the Sol Emeralds she had already found.

Some time later, Dr. Nega was chased into Mobius Prime by the Zone Cops with the blue Sol Emerald secured and hidden in a capsule. The capsule was eventually lost in an altercation before Nega fled form Mobius Prime. By using the grey Sol Emerald to track it down, Blaze returned to the Prime Zone to retrive it. Shortly after arriving she was joined in her quest by Amy Rose, Cream the Rabbit, and Cheese the Chao, forming Team Rose, resulting in a mad-cap chase between Team Dark, the Babylon Rogues and Team Hooligan to recover the gem. After a long chase and many battles, Blaze eventually retrieved the Sol Emerald and returned home with it.

Etymology
"Sol" translates to "sun" in a variety of languages, and is the origin of the word "solar".

Trivia

 * In Sonic the Hedgehog (2006), there are items called Custom Gems that strongly resemble the Sol Emeralds. Each one gives Sonic a new ability.
 * It can be assumed that the Sol Emeralds are the reason that Blaze has appeared in Sonic's world on several occasions other than in the Sonic Rush series. In the DS version of Sonic Colors, Blaze appeared on the Sweet Mountain due to the actions of the Sol Emeralds, and in the Adventure Mode of Mario and Sonic at the Olympic Winter Games it is mentioned that Blaze used the Sol Emeralds to travel to Sonic's world to participate in the games.