The chapter uses a poetic, autophemenographic text, contemplating the cliffs, built by fossilized micro-algae, species diatoms, as an entrancepoint to a reflection on a planetary ethics of companionship. Rather than approaching the 55 mio year old diatomite cliffs as material from which to extract value, it is suggested that they should be seen as wise ancestors, who can teach us lessons about life, death and time. To frame the discussion, the chapter, firstly, gives a brief introduction to diatom biology and the geohistory of diatomite (sediments of fossilized diatoms), to the author’s intimate feelings of companionship with alive and fossilized diatoms, and to the posthuman autophenomenographic methodology which guides her contemplations of the diatoms. Secondly, the  author discusses the revised understandings of life, death, and time which her efforts to corpo-affectively empathize (symphysize) with alive and dead diatoms helped her to establish. She also accounts for the ways in which these revisions are sustained by a vitalist materialist and immanence philosophical approach. In an open-ended conclusion, she suggests an ethics of planetary companionship, based on the contemplations of the corpo-affective bonds, she has established  with the diatoms.