The Elessar is a green jewel with healing properties.
to be edited
In Gondolin, the Elessar was made by Celebrimbor and later changed hands frequently. It was used to try and heal Narminco of his paralysis after the Anghabar cave-in, with limited success. Later it passed to one of Elentirmo's orphans, little Ellen, who took it down Sirion and to Balar with her.
(further editing necessary.)