Ben Lomond is a rhyolite

Rhyolite

This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...

 lava dome

Lava dome

|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...

 near Lake Taupo

Lake Taupo

Lake Taupo is a lake situated in the North Island of New Zealand. With a surface area of , it is the largest lake by surface area in New Zealand, and the second largest freshwater lake by surface area in geopolitical Oceania after Lake Murray ....

 in New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

's North Island

North Island

The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...

. Located about eight kilometres north-northeast of Kinloch

Kinloch, New Zealand

Kinloch is a small but growing town on the most northerly bay of Lake Taupo, northwest of Taupo on the North Island Volcanic Plateau of New Zealand. It is in the Waikato Region....

, it rises to a height of 744 metres above sea level.

Ben Lomond erupted about 100,000 years ago, producing two lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 lobes that flowed around 3.5 kilometres south and southwest from a vent about one kilometre south of Poihipi Road. Much of the lava formed grey banded obsidian

Obsidian

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth...

 as it cooled. Crystalline rhyolite and pumice

Pumice

Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...

were also produced.