Gold Rings

Gold Rings or simply Rings(リング Ringu?) are yellowish-gold, circular shaped objects with a similarly shaped vacant center. It has been a collectible stable of the franchise ever since Sonic the Hedgehog(game) and continues to be vitally important for survival. Collecting and maintaining a certain amount at the end of each Act, Stage, or/and Level provides benefits and bonuses in the game. Although there is no story-related information nor relevance in comparison to the Chaos Emeralds, Rings still serves various purposes.

Sustainability
The primary consistent feature of Rings is sustainability of a character's life. When one or more is collected, the character will not instantly die from contact by dangerous enemies and obstacles. Instead, Rings will wildly scatter away from the character's inventory and will disappear if he or she does not recollect it within five seconds. This aspect also transfers to when certain characters are in their super forms, but with slightly different game mechanics. Within the super state of a character, he or she will not lose rings when in contact with an enemy or obstacle. Rings act as a timer and must constantly be collected to maintain the character's super form throughout the level. If a character fails to do so, his or her super form will be lost with the ring count at zero and will be vulnerable to dying. Fifty Rings must be collected after obtaining all the Chaos Emeralds for a character to successfully transform into his or her super form.

Bonuses
The second dominant feature of Rings is providing bonuses to a character. Besides destroying multiple enemies, Rings also contributes to the Score(usually located at the upper left hand corner of the player's screen) during the level and adds to the total amount at end of each one. The player will hear a brief triumphant tune signaling he or she has the specific amount needed to earn an Extra Life. Extra Lives are also usually earned by collecting one hundred(100) Rings within a level. In a Special Stage, an extra Continue is rewarded to the player who collects fifty Rings and essential to progress towards getting a Chaos Emerald in certain games like Sonic the Hedgehog 2. Another bonus is its ability to act as a energy source such as for Sonic's signature Boost skill. The exceptions that do not follow the basic principles of sustainability and certain bonuses of Rings is drowning, falling into a bottomless pit, failing to complete a mission or level before the time limit expires, and being crushed by obstacles. Sonic Colors(Wii version), Sonic Unleashed(PS2/Wii versions), and Sonic Lost World are the only games that do not award the player an extra live for collecting 100 rings.

Currency
Rings have been confirmed to have monetary purposes ever since its implementation into slot machines of Casino Night Zone from Sonic 2. However, the purchasing and store-related aspects were not visibly shown nor inserted until Sonic Adventure 2 introduced the Chao Black Market. Other games with these features allows a character to buy items needed to enhance a Chao or/and add upgrades to his or her equipment like in Sonic Riders. Because of the various uses of Rings, the best description for it is "power money". Rings also have other variants like the Giant Ring along with being contained in Monitor/Item Boxes usually numbered from 10 to 100.