Abstract: The present disclosure relates to roofing granules, such as solar-reflective roofing granules having one or more of low crystalline silica content, high stain resistance and algae resistance. The present disclosure provides a mineral roofing granule having at its mineral outer surface a first fired mixture comprising an aluminosilicate clay, the first fired material having no more than 2 wt % crystalline silica. The present disclosure also provides a mineral roofing granule having a mineral body and a mineral outer surface, the mineral roofing granule having at its mineral outer surface a first fired material, the first fired material being a first fired mixture comprising an aluminosilicate clay; one or more of a feldspar, a sodium silicate and a nepheline syenite; and, optionally, a zinc source.

Abstract: The present disclosure relates to roofing granules, such as solar-reflective roofing granules having one or more of low crystalline silica content, high stain resistance and algae resistance. The present disclosure provides a mineral roofing granule having a mineral outer surface having a surface porosity of no more than about 10%. The present disclosure also provides a mineral roofing granule having at its mineral outer surface a first fired mixture comprising an aluminosilicate clay, the first fired material having no more than 2 wt % crystalline silica. The present disclosure also provides a mineral roofing granule having a mineral body and a mineral outer surface, the mineral roofing granule having at its mineral outer surface a first fired material, the first fired material being a first fired mixture comprising an aluminosilicate clay; one or more of a feldspar, a sodium silicate and a nepheline syenite; and, optionally, a zinc source.