Ashstone is a kind of volcanic rock formed from fine volcanic ash. During an explosive volcanic eruption, fragmentation of the magma can result in the formation of volcanic ash, consisting of sand-sized or smaller particles.

After settling and consolidation this volcanic ash can be considered to be an ashstone; a more widely accepted term is tuff.

Other articles related to "ashstone":

Palmerston, Australian Capital Territory - Geology
... A layer of ashstone has been folded to form 75 meter wide exposures on the surface ... A syncline determines the western side of the ashstone, with an anticline further to the west ... It forms the eastern limit of the ashstone ...
Geology Of The Australian Capital Territory - Lithology - Late Middle Silurian
... Narrabundah Ashstone is a member of the Canberra formation and is found is eastern Narrabundah and in a geological monument along Fairbairn avenue ... Ashstone is a fine grained tuff ... In addition to the ashstone the Canberra Formation has layers of green-grey to redish dacite, also tuff, quartz andesite, but mostly it is calcareous shale, limestone or sandstone ...
Uriarra, Australian Capital Territory - Geology
... A fine ashstone bed called Tarpaulin Creek Ashstone Member outcrops in a distorted north south line acts as a marker ... Tuff and flows above and below the ashstone member contain obvious pink feldspar crystals ...