Produces trace amounts of Essentia (4 per day). There is no way to build an Essentia Vein, it must be found.

Most Essentia Veins are on a timer. When the timer expires, the Vein explodes and produce a crates. However, Essentia Veins can be upgraded using Halls of Vrbansk. When they get upgraded the timer gets reset to 60 days, allowing the vein to continue producing essentia for an extended period. Upgrading multiple times in a row doesn't help, because the timer doesn't get extended, it gets reset. So you typically want to wait until the essentia vein is mostly exhausted before you upgrade it.

Eveins on colonies controlled by the Trel automatically reset their timers every day without upgrading.  Once the Trel lose control of the colony however that is no longer the case.  

If the colony containing an evein is abandoned the timer on the evein will still continue to count down and the evein will self-destruct.  Eveins without timers however will not do this and will remain until the next player colonizes the planet or the planet is destroyed.

Those Essentia Veins that are not on a timer do not expire and will remain on a planet until demolished. It is unknown if upgrading an Essentia Vein without a timer will convert it to one with a timer.  If you do happen to possess one it's probably better not to try and find out.

Essentia from the Essentia Veins is delivered about 7 hours after server reset.

Essentia Veins are immune from spies running "Appropriate Tech" missions, extraction from Excavators.

Essentia Veins can not be downgraded.