Complex sentence: Black Kryptonite seems to be the rarest form of Kryptonite yet, and appears to be created through intense heating of Green Kryptonite, meaning that it could be considered partially artificial.
Split into simpler sentences: Black Kryptonite seems to be the rarest form of Kryptonite yet, and appears to be created through the intense heating of Green Kryptonite. This means that it could be considered partially artificial.