Lesser known than a cross that was returned from the US to Nagasaki’s Urakami Cathedral in summer 2019, the bricks from the Cathedral were brought to Tainoura church on Gotō islands, to refurbish its façade, while the original Cathedral was entirely demolished. This paper, in comparison to these cases in Nagasaki, examines the ways in which materials that had been affected by the atomic bombing came to be consecrated, forming a part of Hiroshima’s civil religion. In postwar Hiroshima, where residents were selling wreckages of the bombing to the Allied soldiers who were visiting the ground zero, a geologist, Nagaoka Shōgo began to collect stones, first, to estimate the power of this new weapon by examining the melted surface of granite, and then, to evaluate the accurate hypocenter by studying the damage and the distance. Soon, he gathered and preserved objects other than stones—burnt personal belongings, melted glass pieces, charred artifacts—left out in the city. Nagaoka, eventually, donated ever growing collections to the city, and in turn, was appointed as the director of the Hiroshima Peace Museum. Once displayed at the Museum as important witnesses of the bombing, they came to be treated as sacred objects. Tracing their transformation from commodity, to scientific objects, and sacred relics will illustrate the emergence of the city’s civil religion, and thereby, I believe, will offer a new perspective to the discourse of religion and materiality, with particular attention to what generates and sustains such a transformation of materiality.