Normally once a blood stone has been used, the star stone can be converted back into one through sacrifice. Once used, the blood stone will revert to an inert star stone. When the Source Hunters find a blood stone, they are able to carry it in this stable state until they wish to use its healing powers. This will allow the Weaver of Time to partially repair the Tapestry, and reactivate portals at the End of Time. When the Source Hunters come into contact with a star stone (which appears as a blue gem), the stone's energy is completely drained as the duo reabsorb parts of their identity as Guardians. It was discovered that through sacrifice, a Star Stone could be converted into a Blood Stone, an artifact that could be used for both healing or harm. These threads rained down on Rivellon, becoming stones filled with great Source power. Star stones are threads torn from the Tapestry of Time by the Guardians, in an attempt to undo the lapse in their duty which resulted in the freeing of the Void Dragon and the corruption of Source. Star stones, also known as blood stones or inert stones are quest items in Divinity: Original Sin Background

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