If Micronus Prime and his massive supplies of energy can be likened to a living battery, then his Chimera Stone is the conduit through which he focuses his power. As his chosen artifact, he can channel his energy to any other member of the Thirteen; while connected, the stone allows him to direct his energies to best suit the needs of his allies.
Shortly after the birth of the Thirteen, Solus Prime created the Chimera Stone for Micronus Prime using her forge. Micronus used it often as the Primes prepared for their battle against Unicron, adding his own power to Solus's strength as she worked to build weapons and armor for the Primes.
After the death of Solus Prime, an incensed Micronus used the Chimera Stone on Onyx Prime; as the Primes interrogated Megatronus about his part in Solus's death, Micronus angrily channeled some of Onyx's power to transform into a furious, animalistic version of himself.