Create a magical artifact in the form of a glowing stone with green light. The stone pulses like a heartbeat, slightly growing and shrinking in size with each 'beat.' Inside the stone, glowing green energy streams flow, intertwine, and shimmer, creating an effect of dynamic, mystical energy. The background remains transparent to emphasize the brightness and magical nature of the artifact. The glow effect is slightly blurred to enhance the stone's ethereal, magical feel