Eyeglass Island Library
The Eyeglass Island Library, also referred to as the Eyeglass Isle Library, is a building featured within Oracle of Ages. It is an essential location to visit if Link wishes to enter Lord Jabu-Jabu and receive the seventh Essence. It is located on Eyeglass Island, which is in the Zora Seas. In the present, the library is abandoned, but in the past, Link can open the library with a key given to him by King Zora after Link has saved his life.
In the library, Link learns that Veran has cursed the Fairy Queen, so she cannot protect the Zora Seas from getting polluted. Link needs to get Fairy Powder, located in the the back room of the library in the past, to return the Fairy Queen to her original self. To get to the Fairy Powder, Link must get the Book of Seals in the back room of the library in the present. After transforming the Fairy Queen to normal, the Zora Seas will become clean, and Link can enter Lord Jabu-Jabu to receive the next Essence of Time.