The ring is a symbol of eternal love, commitment and completeness. In particular, the engagement or wedding ring which holds a stone. This adds to the metaphorical symbol of the ring: flawless, beautiful and a durable diamond to solidify the concept. A diamond ring as a marriage proposal was introduced into tradition sometime around 1477 when Austria’s Archduke Maximillian proposed to the then Duchess of Burgundy, Mary. Over the following centuries diamonds became more and more readily available to the point where it was not only the rich and wealthy whom were able to wield this all-powerful ring. Now anyone can use this symbol of power to express their heart, will or other limitless possibilities when joined together in marriage.
This token of joining has become the inspiration for many hopeful partners to overcome the fear in their stomach and ask the most important question using a physical symbol of their intangible love. What better symbol of strength, wisdom and coming together to base dozens of heroes (or villains) on than the ring. Many of the symbolic identities of the ring have been incorporated into the special qualities of these power rings I am about to mention.
The idea of the heart being incorporated into a ring with more than just the metaphor, was one that Ma-Ti used to share sympathy and passion to fight the evils of the world in Captain Planet. The other 
planeteers wielding the four elements (earth, fire, wind, and water) through their rings were capable of anything through will and teamwork. Of course they had the extraordinary ability to combine their ring powers and summon Captain Planet (probably from some celestial plane of existence), however, there is also a glaring weakness to their rings as they had to give up their powers to call forth the planet’s ultimate fighter. The rings, as individuals are mediocre in their abilities but when all five teenagers work together they are much more effective. To take that idea one step further as mentioned earlier joining the rings multiplies their power by a factor of five, but at a cost, making them about as useful as you high school ring.
Another interpretation behind what a ring is capable of, is the lovingly thought of bringing together two individuals and helping each other become anything they want. A pair of rings, belonging to siblings has the exact same ability allowing the Wonder Twins to become anything Zan and Jayna want. Well almost, they were limited as one could become any animal, and the other any form of liquid. But it still remains, the notion of two beings coming together to better each other can be seen as the twins have to physically touch their rings (their heroic saying is not a requisite) to harness their power . This need for each other handicaps this ability in poetic limitation; without one the other is simply a piece of jewelry.
The ring stirs all sorts of emotions in the wearer, ranging from passion to avarice. The powers bestowed to the Green Lantern Corps and their fellow ring-slingers takes the emotions behind the ring literally. Each corps is the embodiment of seven emotions including two additional corps for life and death. These power rings have the well documented capabilities for creating constructs out of light, flight and even a protective barrier around their wearers bodies. These rings seem limitless, the only vulnerability of the ring being the wielder’s mind as well as being a slave to that ring’s particular designated feelings (pros and cons) on the emotional spectrum. This war of emotions that can rage within someone was colorfully illustrated, but is also a huge setback for wielding one of these rings. A another glaring weakness for the rings is to their opposite emotions on the spectrum (i.e. fear and will opposed each other), leaving plenty for them to overcome. During the golden ages, the weakness of this willfully strong ring was wood. Proving that material objects are a weakness to the emotions. Throughout the continuity of the Green Lantern, there have been many Earth sector guardians, each specializing in various uses of their rings. It doesn’t matter if it’s Hal and his overly willful mind, Guy Gardner and his warrior spirit, John Stewart and his architectural detail or the imaginative artist Kyle Rayner. Each of these rings were held to an emotional standard with limits, weaknesses and awesome power.
Again, like the wedding band, there is a wonder locked away within the key stone that gives great power to its wearer, allowing him to protect his Keystone ( or beloved city). The Flash hides away his costume protecting his secret identity, but summons it from a pocket dimension in a ring allowing him to defend the citizens of Central City. This same idea has been seen once before this time the rock of the ring changes flesh to stone. In an odd cartoon, loosely based on the Fantastic Four, Ben Grim as a teenager used his pair of rings to transform from a mere man into the Thing with a signature cry of “Thing ring do your Thing”. This can be taken to mean that while wearing a ring, a man can be more than a man, he can be changed into a hero.
A lesser known hero who also used his ring to hide a special item to replenish his powers as they fail, would be Underdog. Not only heroes have used the ring to hide something that they cherish. A very notable villain has used a ring to store a portion of his soul and become nearly indestructible, however, this also leaves He Who Must Not Be Named vulnerable. Voldemort from Harry Potter is entrusting his life to the strength of a ring as he uses one as a magical item dubbed a Horcrux. Coincidentally, the Horcrux was also part of a trio of items, The Deathly Hallows, where in the stone of the trio granted the bearer of the ring the ability to resurrect the dead. To Further support this notion of keystone power the fear of being identified or losing ones powers and life are the complete opposite ideology to the diamond rings flashy almost narcissistic notion.
Of course the stone inset in the ring holds a huge factor in the lure of the jewelry. The bigger the karat the higher the price point of a ring, but in the case of comic books, the strength and the effect the stone has not it’s size is where the value lies. The value of these rings range from matter rearrangement to elemental powered blasts. The formation of a diamond is attributed to geological and scientific processes that require many factors working in perfect harmony to create these beautiful stones. In the case of this next set of collected artifacts, the souls of cosmic warriors are trapped within these rings giving them powers on a universe threatening level. The Mandarin’s ten rings are nearly unstoppable. Although every villain has a weakness, The Mandarins’ being the rings react to each other with an electrostatic field, something that Iron Man used to his technological advantage with magnets. On a singular level the rings are powerful, and one would think with all ten of these Makluan Rings that there wouldn’t be anything to stop you, but sometimes too much of a good (or bad) thing can be your downfall.
Many times, a ring has the effect to bring men and women to their knees due to the symbolism behind the piece of jewelry or even by the rings stunning beauty and expectation of surprise. One of the most power rings in the DC comic book multi-verse is worn by an ordinary man, and holds the power to bring an extraordinary man to his knees. This ring itself has no powers, it doesn’t grant the you flight like the rings worn by the Legionnaires allowing them to fly and communicate with each other or won’t give 
you the power to save the universe like the Green Lantern’s mentioned earlier. Instead, this ring only holds a rare rock from a destroyed world, Krypton. It allows the human portion of the World’s Finest team to diminish the all powerful alien hero making it one simple but powerful weapon. Batman’s Kryptonite ring holds one of the most powerful rocks as its metaphorical diamond, holding leverage and acting as a fail-safe against Superman. Being the most powerful life form of their world it could me the end if he were ever to lose control.
In terms of jewelry, there are some equally if not more powerful items in other geekdoms outside of comics. Technically speaking in terms of Dungeons and Dragons rules, one character can wear two rings, each granting them a variety of powers, perks, or buffs. The equipment list of other powerful accessories ranges from armbands (Wonder Woman’s bracelets), cloaks (Dr. Strange’s Eye of Agamotto), or the all mighty gauntlet (see Infinity Gauntlet). Being a close relative to the Dungeons and Dragons realm of magic and powerful rings, it is easy to make the short leap to The Ring. One Ring to rule them all, One Ring to find them, One Ring to bring them all and in the darkness bind them. The powers of this One Ring were meant to control and dominate the other twenty rings and grant it’s wearer other darker powers that only a stronger willed being could unlock. There are many times in the Lord of the Rings trilogy that The One Ring was eluded to having greater powers as well as being much stronger than we perceived. In another Lord of the Rings spinoff the Shadows of Mordor, we see the rings power in more detail with some overly descriptive writing and the ability to walk in the wraith world. Like every ring on this list the One Ring isn’t with a weakness, being a ring that wears down your soul and will to the point of obsession (Gollum), and the true potential of this ring holds itself in reserve for true evil. In the end the ring wears you, and not the other way around. This unexplored powerful ring has been referenced and used as inspiration all over, most recently in the Teenage Mutant Ninja Turtles 2012 cartoon where Michelangelo wields a +1 ring of awesome that he treats with admiration paralleling Gollum.
In the end, there are countless rings with numerous abilities and powers that enhance the wearer. That is the point of the initial idea behind a ring, to decorate and beautify the wearer with an expressive aesthetic that sometimes only jewelry can provide. As the tradition grew and they became the symbols of strength, power and heart so did these fictional rings. Each one evolving as we did. Which is a nice way to bring this to a conclusion. For many wearing a ring (real or fictional) it can make them feel as though they are filled with power and emotions that almost seem unreal. Though the engagement and wedding ring has a supposed origin point, the idea of a magic ring holds its place in human history dating back to classical antiquity. This list has many of the magic an otherwise special rings, but there are of course other rings not mentioned here; any version of Dungeons and Dragons with enchanted rings, the Power Ring of DC Comics Earth-3, or even down to the magic ring in Tom and Jerry and The Magic Ring. No matter what the ring or where is comes from jewelry can hold power in our reality and those of imagination but it’s always the wearer of that jewelry that is truly where the power and meaning comes from. Weather its Hal Jordan or your future wife each ring is just as powerful in the eye of the beholder and can be capable of changing the world.