Sourstuff (Token O) is the eighth firststuff. The kernals of Sourstuff have eight firstbits and eight, nine, or ten (though most often eight) evenmotes. Sourstuff most often forms two bonds. It can be found alone as a two-uncleft loft (O2), but will band together with other stuffs when it can, in what is called besouring. Besouring gives of heat; swift besouring is fire, while slower besouring drives living beings. For this thing, sourstuff is needed by most lifekinds.
When besouring lifeworthy minglestuffs, the main outputs are water (H2O) and wortloft (CO2). As well as being found in the loftsea and as the main firststuff (by weight) in water, sourstuff makes up nearly half of the stone in the Earth's hull.