Item. Dark-green, mysterious deep color which can enchant any living being is not the only advantage of the artifact: it boosts the movement of Vespene gas molecules, allowing an easier extraction from the depths and increases the base output of gas by 1%. (With each successive artifact effect falls). Also, the emerald artifact improves the shields of defensive units on the planet (including shield regeneration) by 1%.

The effect of several artifacts is summarized, does not occupy fields.

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The artifact can be stolen in case of a successful attack, if the attacker has indicated "vespene" as a priority exported resource when sending off the fleet. The artifact cannot be in a fleet, which has no units for the transportation of the artifact. If the artifact was left without fleet’s units, which able to transport it or without the fleet, it will be destroyed.
Artefact can be eaten by Lexx.
It can be built in the Workshop. The recipe can be found in an expedition in the Babylon sector, which includes a Science Vessel (for Humans), a Queen (for Xerjs) and a Investigator (for Tosses), with a probability proportional to the expedition time in days.