Argon Crystal

Argon Crystals are a rare resource that drops in the Orokin Void and from Councilor Vay Hek. Unlike other resources, they decay over time with a half-life of 24 hours. After this period the resource will disapear from the user's inventory and must be reacquired if needed.

Gathering Tips
Tower 1 survival is a great way of getting these.

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

Trivia

 * Argon (or Ar) is a chemical compound on the periodic table of elements, and is labeled as a noble gas. Its decay may be the result of it sublimating at room temperature.