A roofing granule can include a base particle having a base material and a layer covering the base particle of the roofing granule. The layer can has a first material and a second material that includes a metal carbonate, wherein the first and second materials include a same metal element, and the base material is different from the first material. In a process of forming the roofing granule, the layer can have pores. The process can include infiltrating a fluid into the pores of the layer while the base particle is present and adjacent to the layer, wherein the fluid includes a carbonate. The process can further include reacting the carbonate with a metal compound within the layer to form a metal carbonate within the layer. The roofing granules can be used in roofing products.