It is the Leviathan cross or BrimstoneSymbol. In Alchemy, the Leviathan's cross is a symbol for Sulfur, which is oneof the three essential elements of nature and spiritually analogous to thehuman soul.
Alchemically, Sulfur has the qualities ofmasculine, hot and dry and combined with Mercury (feminine, cool and moist),the pair were considered the parents of all metals. Depicted on the bottom isan infinity sign, and above is a double cross. The Double cross symbolizesprotection and balance between masculine and feminine energies but can also beseen as a stroke-through "equal-to" (=) to show that every person hastheir own life; humans as their own centrum of balance, and truth. The infinitysign underlines the constant and infinite nature and most likely symbolizes theeternal universe and the balance between material and spiritual world.
Another possible interpretation of theinfinite sign could be two ouroboros, representing the cycle of Life itself.The association with the Leviathan makes it a symbol of depth and surfacing andcan be interpreted as a sign of free choice. The Leviathan Cross origins mightbe linked to the the knights templar use of the cross of Lorraine carried bythem on their Crusades.