Ring of invisibility

The 'Ring of invisibility was a jewelled ring that would turn its wearer invisible if worn and then rubbed. After the magic wore off or if the ring was removed, the ring would disappear. The ring is gold with a breathtaking tiger's eye stone perched on top.

Background
As Graham walked through Daventry on his quest for the crown, he came across an elf with whom he stopped to chat. This so surprised the small elf that he gave Graham a gold ring embedded with a tiger's eye stone. The ring was magic and, if rubbed, had the ability to turn the wearer invisible for a while. Graham used the ring accidentally, but the accident saved his life.

Graham accidentally rubbed the ring while it was in his pocket, causing him to turn invisible. However, the accident saved him from an ogre and a dwarf. He later entered an inviting mountain lake to take a swim. When he entered the chill, fresh water, the magic ring slipped off of Graham's finger, making him visible again.

The ring is quite similar to the enchanted ring given to Rosimond by a fairy.

Behind the scenes
Likely inspired by the One Ring of Tolkien fame, and other rings of invisibility from classic fantasy, such as the tale of Rosimond.

The ring's appearance differs in each vesion of King's Quest 1. In original it is gold with a brown tiger's eye jewel. In the remake it is gold and purple band, with a blue jewel.

There are multiple ways of using the ring throughout the different versions of King's Quest 1. Due to different format of puzzles in each in one. The ring can be used to get past most enemies in both versions.

If Graham takes too long, the spell will weaken, and the ring disappears.

In the original it works against the thief, sorcerer, ogre, giant, witch, and wolf. Using the ring will lead to losing 2 points in the original KQ1, after the ring disappears from the inventory.

In the KQ1SCI remake it works against the thief, dragon, and giant (it does not work against the wolf or the Sorcerer in the remake ).

It will only partially work with the Ogre. If you are far away enough, you may be able to escape, if he gets to close he'll sense you.

The ring will not work against the giant rat, troll or the leprechauns. It does not function inside the Gingerbread House.

Alternatively the magic of the Fairy Godmother or the Magic Shield (in original) can be used in the same situations (the shield will not work against the dragon).

In KQ1SCI its possible to use the ring more than once, if it is removed from Graham's finger while he is invisible, it remains in his inventory. In the original removing the ring will cause the ring to disappear.

In both games almost any small fall will make graham lose the ring, if he is wearing it while climbing.

Peter Spear through his conceit that the character Derek Karlavaegen has been noted to claim that the original account is the most accurate story of how the ring was used (so its surprising to note that this would lead to incomplete score by the end of the game in the original).