Argon Crystal

"Void based radioactive resource that decays every day it is out of the Void."

- In-Game Description

Argon Crystals are a rare resource that drops in the Orokin Void and from certain Assassination targets. Unlike other resources, they decay after a limited period of time. After this period the resources will disappear from the user's inventory and must be reacquired if needed.

The timer points towards Midnight UTC/GMT+0 time indefinitely. This supports its description.

Gathering Tips
''These are based on opinions and may not be 100% true. These should be viewed as advice for finding the materials until better facts are proven.''
 * Argon Crystals drop more commonly from containers and lockers. Thief's Wit, Master Thief, and a Kubrow or Kavat with Scavenge can help in finding containers that may contain Argon Crystals.
 * Bringing a Nekros with Desecrate can improve your chances in finding Argon Crystals.
 * Bringing a Hydroid with the Pilfering Swarm augmentation can improve your chances in finding Argon Crystals.
 * Bringing an Ivara with Prowl can improve your chances in finding Argon Crystals
 * Defense missions are a good method of farming Argon Crystals, as all enemies will come to you. Combining this with a Nekros with Desecrate and using slash weapons to dismember the bodies (Desecrate counts each severed part as a separate entity) will give you a high chance for drops.
 * Survival missions are a safer (albeit slower) way to farm Argon Crystals, as enemies will spawn indefinitely you can extract immediately after you have the amount of crystals you need. This also lowers the chance of wasting crystals if you only need a certain amount.

Blueprints Requiring Argon Crystals
Click to view the Blueprints requiring Argon Crystals. 

Trivia

 * Argon (symbol: Ar) is the 18th element in the periodic table. It is a noble gas whose most commonly occurring isotope is stable and does not decay as the Argon Crystal does (though it has a number of unstable isotopes that do decay).
 * While argon does sublimate at room temperature, sublimation doesn't follow the pattern of being repeatedly cut in half at regular intervals.
 * This is the first resource that has the ability to degrade over time.
 * Due to a DDoS Attack on Warframe's PC Servers on April 15, 2014, Argon Crystals didn't decay until servers stabilized – although their countdown remained active. This lasted until  was launched, as the servers had fully recovered by that time.
 * Previously, Argon Crystals would drop from Infestation Outbreaks (particularly from Phorid), and was considered a much more efficient way to collect them. This bug was removed (albeit undocumented in the patch notes) in.