 cellspacing="0" | H2S || + || 2 O2 || → | colspan="5" | H2SO4 || (sulfide oxidation) |- | H2SO4 || + || 2 H2O || → | || + || colspan="3" | 2 H3O+ || (sulfuric acid dissociation) |- | CaCO3 || + || 2 H3O+ || → | Ca2+ || + || H2CO3 || + || 2 H2O || (calcium carbonate dissolution) |- | Ca2+ || + || SO42- || → | CaSO4 || || colspan="3" | || (formation of calcium sulfate) |- | CaSO4 || + || 2 H2O || → | colspan="5" | CaSO4 · 2 H2O || (formation of gypsum) |
<coherence>  cellspacing="0" | H2S || + || 2 O2 || → | colspan="5" | H2SO4 || (sulfide oxidation) |- | H2SO4 || + || 2 H2O || → | || + || colspan="3" | 2 H3O+ || (sulfuric acid dissociation) |- | CaCO3 || + || 2 H3O+ || → | Ca2+ || + || H2CO3 || + || 2 H2O || (calcium carbonate dissolution) |- | Ca2+ || + || SO42- || → | CaSO4 || || colspan="3" | || (formation of calcium sulfate) |- | CaSO4 || + || 2 H2O || → | colspan="5" | CaSO4 · 2 H2O || (formation of gypsum) |
 cellspacing="0" | H2S || + || 2 O2 || → | colspan="5" | H2SO4 || (sulfide oxidation) |- | H2SO4 || + || 2 H2O || → | || + || colspan="3" | 2 H3O+ || (sulfuric acid dissociation) |- | CaCO3 || + || 2 H3O+ || → | Ca2+ || + || H2CO3 || + || 2 H2O || (calcium carbonate dissolution) |- | Ca2+ || + || SO42- || → | CaSO4 (formation of calcium sulfate) |- | CaSO4 || + || 2 H2O || → | colspan="5" | CaSO4 · 2 H2O || (formation of gypsum) |