Sulfur dioxide (SO 2) is a colourless gas with a sharp, irritating odour. It is produced by burning fossil fuels and by the smelting of mineral ores that contain sulfur. Erupting volcanoes can be a ...
Usually, gold is locked within Earth’s mantle. But scientists have long suspected that sulfur, which forms strong chemical bonds with gold, allows it to be transported in magma up to the surface.