Ezekiel 28:14 states, "Thou art the anointed cherub that covereth; and I have set thee so: thou wast upon the holy mountain of God; thou hast walked up and down in the midst of the stones of fire."
Ezekiel 28:16 adds, "By the multitude of thy merchandise they have filled the midst of thee with violence, and thou hast sinned: therefore I will cast thee as profane out of the mountain of God: and I will destroy thee, O covering cherub, from the midst of the stones of fire."
I have always thought that the "stones of fire" were probably the stars. God's holy mountain is probably a reference to heaven. In a parallel passage (also referring to Satan as does this passage), the devil vows in his heart, "I will ascend into heaven, I will exalt my throne above the stars of God" (Isaiah 14:13). Finally, the devil is designated as "the prince of the power of the air" (Ephesians 2:2). This all seems to point to the stars. Perhaps someday I can be more sure than I am now. God bless.