Keystone

The Madrigal Forerunner artifact is an unknown Forerunner artifact that was buried on the planet Madrigal.

Operational history
In 2552, the Covenant launched an attack on Madrigal for the artifact, wiping out a nearby Insurrectionist outpost. The Spartans of Silver Team eliminated the attacking Sangheili and John-117 and Riz-028 entered the cave where the Covenant had been excavating for the artifact. Upon finding the artifact, John touched it and the artifact reacted to the touch of a Reclaimer, lighting up the entire cave and displaying symbols. It had a surprising effect on John, apparently unlocking some of his sealed memories of his childhood. The artifact's reaction to John was noticed by a surviving Sangheili who managed to escape and report it back to the Prophet of Mercy who had learned of the artifact's location from Makee.

Throughout his return trip to Reach, John remained fascinated by the artifact while Dr. Catherine Halsey became concerned about its effects on John and his memories. After John rebelled rather than execute Kwan Ha, the UNSC shot down his Condor with an electromagnetic pulse, knocking the artifact loose from its casing in the process. John touched it, causing the symbols to display once again and for John to experience more of his memories. In one of his memories, a young John drew a picture of the artifact for his mother. The artifact then let out a pulse that knocked out power to the UNSC base while restoring power to John's Condor, allowing John to escape from Reach with Kwan and the artifact.

Gallery
 File:HTV Madrigal Artifact.png|Chief activates the artifact File:HTV Madrigal Artifact Symbols.png|Forerunner symbols are displayed to Chief. File:HTV Madrigal Artifact Reclaimer.png|Reclaimer identified File:HTV Madrigal Artifact Reach.png|Chief activates the artifact on Reach File:HTV Madrigal Artifact Reclaimer Symbol.png|The artifact recognises Chief as a Reclaimer File:HTV Madrigal Artifact Sketch.png|Chief's childhood drawing of the artifact 

List of appearances

 * Halo: The Television Series
 * Contact