Data Crystal

Rather than use magnetic, optical, flash drive or solid-state drive based information storage mediums, in the future there will be ways to read and write data onto transparent crystaline solids. This jump in technology usually makes each Data Crystal a veritable Bag of Holding for information, uploading and downloading entire planetary databases in seconds. The crystals may be shaped like quartz, techno Crystal Balls or as diamond or gem cut jewelry.

Data Crystals often double as video recorders and Hologram emitters, allowing owners to record, store and project their home movies. Because Power Glows, these Data Crystal hologram projectors can often even do without an external power source.

Sub Trope of Power Crystal and Mineral MacGuffin, often used by resident of Crystal Spires and Togas.

Anime and Manga

 * The Gosroth's log in Crest of the Stars takes the form of a data crystal, which is passed on to Lafiel and Jinto when they're ordered to flee an impending battle.
 * A major MacGuffin in Battle Angel Alita: Last Order is an ancient computer program encoded on a crystal.

Film

 * In Superman II, Superman's Fortress of Solitude at the North Pole had a system that stored information on crystals.

Literature

 * Star Wars has holocron crystals.
 * One of the characters in the Wild Cards series is Jube the Walrus. As an agent of the interstellar trading consortium known as the Network, he has advance technological devices such as recording crystals that can store information.

Live Action TV

 * Space Cases: The Android Thelma exhibited odd behavior throughout the show due to a memory crystal that Harlan accidentally damaged in the first episode. The main ship in the series, the Crysta, also used similar technology.
 * Alphas, one episode featured a necklace made from some strange crystals, and they figure out that it stores information on specially arranged molecule structures.
 * In the first season of Fringe, there were the glass disks and they were data storage devices, Massive Dynamic was able to read information from them.
 * Farscape, too, had data crystals in several episodes, most notably the navigation crystal in "DNA Mad Scientist."
 * Hyperdrive featured this trope being replaced by even more effective crystals (as a DVD to Blu-Ray analogue).
 * Tracker had this, they were maps stored on crystals. The first one got left behind at an alien-theme restaurant after a fight, but Cole found the second one hidden in a stored museum piece. They were maps of the Lake Michigan area to show the way to the Doomsday Device hidden under the Watchfire bar.
 * Shows up occasionally in Star Trek, primarily in later TNG, DS9, and Voyager.
 * From Star Trek the Next Generation, Isolinear Optical Chips may represent a "missing link" between data crystals and more traditional electronics.
 * In the Stargate 'verse most space-faring species use crystals extensively in their computers. In one case a storage crystal from an old Goa'uld research base is dismissed as a simple decoration by the archaeologists.
 * Data Crystals are a popular intergalactic standard in Babylon 5.

Tabletop RPG

 * Shadowrun. Information can stored on optical crystals ("chips"). This includes cyberdeck components.
 * Starblazer Adventures, based on the 1980's British Comic Book. The Random Key Items/Target of Objective random table lists Data Crystals as a possible target for an Item Mission.

Video Games

 * Final Fantasy X has Spheres, which hold holographic recordings.
 * The Halo series has these and uses them for storing artificial intelligences. Less complex data is simply transmitted.
 * Starcraft, the Protoss are an almost literal Crystal Spires and Togas society and use crystals as power sources and to store their thoughts and knowledge on. The Warp Prism transport in the sequel is actually described as a crystal computer, able to scan lifeforms and machines, convert them to energy and store the data in its databanks, then reconfigure them from energy back into matter.

Web Comics

 * Buck Godot Zap Gun for Hire has "info points", though it's considered quaint.

Web Original

 * In Orions Arm, the "ultimate chip", doesn't look like a single crystal and was originally intended for use as a processor for very advanced distributed computing, can also store massive amounts of data, and is made of diamondoid, which is a crystal.

Western Animation

 * Bionicle: Memory Crystals.

Real Life

 * The reason for this trope is because crystals have been suggested as a storage medium for holographic memory.