This is the Zoroastrian Symbol from S1's "Shadow", specifically this is the alter Sam finds that Meg set up to control the Daevas. I love how much detail was brought out once I fixed the cap: the black skull, the card, bones, the beads, even the blood goblet barely visible at the bottom.
From SuperWiki: Zoroastrian Symbol
A symbol that depicts the human soul before birth and after death.
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