The dominant morphology of halloysite that forms from alteration of feldspars and mica is tubular, whereas that formed from volcanic glass
has a predominately spheroidal morphology (Adamo et al.
The Raman analyses further revealed that the whitish veins between the brecciated volcanic glass
masses consisted of calcite.
Thorseth (1998), "Alteration of Oceanic Volcanic Glass
: Textural Evidence of Microbial Activity," Science 281: 978980
Nakagawa and T Ohba, "Minerals in volcanic ash 1: primary minerals and volcanic glass
," Global Environmental Research, vol.
Rhyolites are composed of volcanic glass
, quartz crystals, orthoclases, biotites and hornblendes as accessories (Bullock et al., 1985).
Volcanic ash can contain significant quantities of respirable particles of rock, minerals, and volcanic glass
, and eruptions also emit hazardous gases such as sulfur dioxide, hydrogen sulfide, hydrochloric acid, and hydrofluoric acid.
(1.) This pumice stone is entirely volcanic glass
and it composes the pasty part of volcanic rock.
The material culture recovered includes 718 basalt artefacts, 24 volcanic glass
artefacts and 755 ceramic sherds.
The only real difference, besides being volcanic in origin, is that the particles consist of fine-grain minerals and volcanic glass
instead of the relatively coarse clay, sand, and silt in a dust cloud.
He struck the black volcanic glass
with the stone in his right hand, picked up the black fragment and drew it across a piece of cloth he held in his hand.
"It's acidic and contains tiny particles of volcanic glass
. And waves crashing with the lava can send out scalding water." It was not clear how long the lava would continue flowing into the ocean.