Carbonatites, probably the strangest rocks on Earth, are often associated with critical rare earth elements, making them increasingly relevant to society. Such deposits are also often associated with enrichments in Nb, Ba, Zr, Sr, Ti and Cu, as well as apatite and fluorite. Through observations of natural and experimental examples I will review our current understanding of how these intriguing enrichments might occur. Most of the key processes involved, as summarised below (Yaxley et al, 2022), will be presented along with numerous real-world examples and rampant speculations.