Using industrial side streams as artificial aggregate precursors could increase waste utilization and save natural reserves. In this study, lightweight geopolymer aggregates were manufactured from fluidized bed combustion fly ash and mine tailings using high shear granulation and alkali activation. The results showed that geopolymer aggregates had physical properties comparable to commercial lightweight expanded clay aggregates (LECAs). Mortar and concrete prepared with geopolymer aggregates had higher mechanical strength, a higher dynamic modulus of elasticity, and higher density than concrete produced with LECAs, while the rheology and workability was the same.