ASH - Volcanic ash - Volcanic ash. Extremely light particles, drifts with the slightest air movement.
Powder category. Colour; dark grey/grey/light grey. Becomes heavy when sampled in large masses. Floats on water. Produces a grey coloured colloid when mixed with water.
ASHG - Ash Gas - Gas form of ASH, drifts upwards and flattens out when loosing upwards speed, before releasing ash.
Gas category. Colour; SMKE/CO2. Drifts upwards, but when loosing it's upwards speed, flattens out and drifts with the wind. When slow enough, turns into ASH and falls. Add for realistic volcanoes.
ASHC - Ash cement - Colloid, produced when ash mixes with water. Hardens over time.
Liquid category. Made from a mix of ASH and WATR. Hardens over time, turns into BRCK when hardened.
ASH: I'm not sure how it would get heavier as you add more of it without causing lag.
ASHG: No. If ASH is light enough, a wood fire would be able to get it airborne.
ASHC: Support, but it should be renamed to CMNT.