Keepsake

There is more information available on this subject at Keepsake on the English Wikipedia.

"It's just... It's sorta like a charm..."

— Parisa

A keepsake in remembrance of Cortana.

A keepsake, memento, or souvenir is a unique item that a person holds to be of special importance, reminding them of a person, place, or event. They range from photographs, holo-stills, trinkets, toys, and other memorabilia. Many are kept out of memory of the person who gave it or originally owned it. Being personal objects, they are mostly unrecognizable to outsiders. Within the United Nations Space Command armed forces, soldiers often pass along their dog tags as keepsakes for their comrades to remember them by. Although generally considered an unseemly act, and in the case of the United Nations Space Command, against protocol, some Covenant and human soldiers were known to keep souvenirs from fallen enemies as war trophies.

List of keepsakes

Individual	Items	Importance	Image
Arthoc	Ravager Rebound	Requisitioned by Arthoc prior to the assault on the UNSC stronghold at the wreckage of UNSC Mortal Reverie, he was so impressed with the weapon's performance, he kept it in his possession after the battle.
Atriox	Chainbreaker	A customized gravity mace forged by Atriox following the Algolis Invasion, whose blades are positioned to evoke the imagery of Doisac and its three moons - Soirapt, Warial, and Teash. This imagery also serves as the basis of the Mark of Atriox - the emblem of the Banished - making Chainbreaker a symbolic scepter of the Banished as a whole.
Benjamin Giraud	African tribal photograph	On October 20, 2552, Ben Giraud toured the streets of Old Mombasa and came across a vendor selling vintage print photographs. He admired the man's prints, having not seen any pictures like them since college, and purchased one depicting tribal Africans. Ben lost the souvenir later that day when the Covenant arrived and attacked Mombasa.
Carter-A259	A holo-still of his mother and father	Carter-A259 had a holostill containing an image of his parents who had perished when the Covenant attacked their homeworld of Biko in 2526.
Catherine Halsey	Dr. Halsey's personal journal	Halsey bought her journal when she was eighteen and used it to record her life for the next 42 years. Inside she wrote personal thoughts, scientific diagrams, potential theories, and sketches of people and places significant to her life.
Chloe Hall	James-005's Mark V MJOLNIR armor helmet	Before sacrificing himself to help Chloe escape, James gave her the helmet from his armor which Chloe would need to communicate with James' AI Lola.
Cortana	Installation 04's Activation Index	Cortana took the Activation Index from its owner 343 Guilty Spark so that he could not use it to fire the Halo ring. The Index's contents put a heavy toll on her memory, due to containing a hundred millennia's worth of biological and technological data recorded on the ring, but came to help as a means to activate Alpha Halo's replacement. When Cortana was destroyed, she left behind fragments of the Index which were taken by Joyeuse.
Daisy-023	Teddy Bear keychain	Daisy once possessed a small teddy bear on a chain which she lost the day she was abducted into the Spartan-II program. Years later, her own flash clone gave one to her. Daisy kept it with her to the day she was killed in action.
Ur-Didact	Backdraft Cindershot	A special Cindershot requisitioned by Bitterness-of-the-Vanquished from the Ferrarius Assembler Vats for the Ur-Didact's personal use as Protector of the ecumene.
Dimah Tchakova	A stuffed toy	Dimah would occasionally comfort herself with a plush toy that she had taken with her to Corbulo Academy.
Emile-A239	Stolen Covenant contraband	Spartan Emile possessed an "impressive" collection of souvenirs taken from Covenant he had killed. This was in direct violation of Subsection Seven of the Cole Protocol, which stated all Covenant items should be scanned for tracking devices before being brought into human territory. However his superiors ignored this, due to being part of the Army instead of Navy.
Fernando Esparza	A holorecorder with a message from a wife and child	During his six months alone in space, Esparza would often watch the holorecorder message. Esparza later revealed that the device wasn't even his originally, but Esparza kept it because the message reminded the engineer of his own wife and daughter, Alitza and Iahlee Esparza.
Frank Kodiak	Type-1 energy sword	During the Covenant war, Frank Kodiak obtained an energy sword from a Sangheili warrior he had killed. Years later, he used the sword in a duel against N'tho 'Sraom, the Sangheili responsible for severing his right arm.	(A standard Covenant energy sword)
Gabriel Thorne	Gek 'Lhar's