Pumice

pumice stonePumicitepumiceousLoisels pumicepumaceouspumice fallsPumice rockspumice stonespumice-stones
Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals.wikipedia
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Pumice raft

large raftlarge volume of pumice createdlong-lived rafts of floating pumice
Eruptions under water are rapidly cooled and the large volume of pumice created can be a shipping hazard for cargo ships. After the explosion of Krakatoa, rafts of pumice drifted through the Indian Ocean for up to 20 years, with tree trunks floating among them.
A pumice raft is a floating raft of pumice created by some eruptions of submarine volcanoes or coastal subaerial volcanoes.

Scoria

reticulitescoriaceousVolcanic scoria
Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls and being dark colored and denser.
Scoria is relatively low in density as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity greater than 1, and sinks in water.

Volcanic rock

volcaniclava rockvolcanic rocks
Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals.
Pumice is a highly vesicular rock produced in explosive volcanic eruptions.

Ignimbrite

ignimbriticignimbrite rockmetaignimbrites
Pumice is a common product of explosive eruptions (plinian and ignimbrite-forming) and commonly forms zones in upper parts of silicic lavas.
Ignimbrites are made of a very poorly sorted mixture of volcanic ash (or tuff when lithified) and pumice lapilli, commonly with scattered lithic fragments.

Rhyolite

rhyoliticrhyolitesliparite
It is commonly but not exclusively of silicic or felsic to intermediate in composition (e.g., rhyolitic, dacitic, andesite, pantellerite, phonolite, trachyte), but basaltic and other compositions are known.
Some rhyolite is highly vesicular pumice.

Plinian eruption

PlinianPlinian eruptionsUltra Plinian
Pumice is a common product of explosive eruptions (plinian and ignimbrite-forming) and commonly forms zones in upper parts of silicic lavas.
The key characteristics are ejection of large amount of pumice and very powerful continuous gas-driven eruptions.

Extrusive rock

extrusiveextrusionextruded
Pumice is composed of highly microvesicular glass pyroclastic with very thin, translucent bubble walls of extrusive igneous rock.
If the magma contains abundant volatile components which are released as free gas, then it may cool with large or small vesicles (bubble-shaped cavities) such as in pumice, scoria, or vesicular basalt.

Volcano

volcanicvolcanoesvolcanic igneous activity
Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano.
Large, explosive volcanic eruptions inject water vapor (H 2 O), carbon dioxide (CO 2 ), sulfur dioxide (SO 2 ), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (10–20 mi) above the Earth's surface.

Lipari

LiparaAbbey of LipariCanneto
On the Aeolian Islands of Italy, the island of Lipari is entirely made up of volcanic rock, including pumice.
As a result of its volcanic origin, the island is covered with pumice and obsidian.

Pyroclastic rock

pyroclasticvolcaniclasticpyroclastics
Pumice is composed of highly microvesicular glass pyroclastic with very thin, translucent bubble walls of extrusive igneous rock.
During Plinian eruptions, pumice and ash are formed when silicic magma is fragmented in the volcanic conduit, because of decompression and the growth of bubbles.

Trachyte

trachytictrachytesorthophyre
It is commonly but not exclusively of silicic or felsic to intermediate in composition (e.g., rhyolitic, dacitic, andesite, pantellerite, phonolite, trachyte), but basaltic and other compositions are known.
Glassy forms of trachyte (obsidian) occur, as in Iceland, and pumiceous varieties are known (in Tenerife and elsewhere), but these rocks as contrasted with the rhyolites have a remarkably strong tendency to crystallize, and are rarely to any considerable extent vitreous.

Volcanic glass

glassyglassbrownish glass
Pumice is considered a volcanic glass because it has no crystal structure.

Vesicular texture

vesicularvesiclesvesicle
Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. Pumice is composed of highly microvesicular glass pyroclastic with very thin, translucent bubble walls of extrusive igneous rock.
Rock types that display a vesicular texture include pumice and scoria.

Felsic

leucocraticfelsic typefelsic rock
It is commonly but not exclusively of silicic or felsic to intermediate in composition (e.g., rhyolitic, dacitic, andesite, pantellerite, phonolite, trachyte), but basaltic and other compositions are known.

Krakatoa

KrakatauAnak Krakatau1883 Eruption of Krakatoa
After the explosion of Krakatoa, rafts of pumice drifted through the Indian Ocean for up to 20 years, with tree trunks floating among them.
A German, Johann Handl, obtained a permit to mine pumice in October 1916.

2012 Kermadec Islands eruption

20122012 Kermadec Islands eruption and pumice raft7,500–10,000 square mile pumice raft
The volcano erupted in July 2012 but remained unnoticed until enormous pieces of pumice were seen to be floating on the Pacific Ocean.
The large volume of low density pumice produced by the eruption accumulated as a large area of floating pumice, a pumice raft, that was originally covering a surface of 400 km², spread to a continuous float of between 7500 and 10000 sqmi and within three months dispersed to an area of more than twice the size of New Zealand.

Pedicure

pedicuristfoot filepedicures
"Pumice stones" are often used in beauty salons during the pedicure process to remove dry and excess skin from the bottom of the foot as well as calluses.
Pedicures include care not only for the toenails; dead skin cells are rubbed off the bottom of the feet using a rough stone (often a pumice stone).

Abrasive

abrasivesbonded abrasiveabrasion
It is also used as an abrasive, especially in polishes, pencil erasers, and the production of stone-washed jeans.

Magma

magmaticmeltmagmas
It forms when volcanic gases exsolving from viscous magma form bubbles that remain within the viscous magma as it cools to glass.
Rocks largely composed of volcanic glass include obsidian, scoria and pumice.

Ring of Fire

Pacific Ring of Firecircum-Pacific orogenic beltPacific Rim
This area contains 19 active volcanoes and it lies in close proximity with the Pacific volcanic belt.
The last eruption of this dominantly basaltic volcano in 1707 ejected andesitic pumice and formed a large new crater on the east flank.

Stone washing

acid washstonewashstonewashed jeans
It is also used as an abrasive, especially in polishes, pencil erasers, and the production of stone-washed jeans.
This is usually accomplished either by washing the jeans with pumice in a rotating drum, or by using chemicals to create the appearance without the use of a rotating drum.

Eraser

eraserselectric eraserrubber
It is also used as an abrasive, especially in polishes, pencil erasers, and the production of stone-washed jeans.
Bits of rough stone such as sandstone or pumice were used to remove small errors from parchment or papyrus documents written in ink.

Concrete

admixturesworkabilitypoured concrete
Pumice is widely used to make lightweight concrete and insulative low-density cinder blocks.
During the Roman Empire, Roman concrete (or opus caementicium) was made from quicklime, pozzolana and an aggregate of pumice.

Exfoliation (cosmetology)

exfoliationexfoliantexfoliating
Today, many of these techniques are still used; pumice is widely used as a skin exfoliant.
Mechanical exfoliants include microfiber cloths, adhesive exfoliation sheets, micro-bead facial scrubs, crepe paper, crushed apricot kernel or almond shells, sugar or salt crystals, pumice, and abrasive materials such as sponges, loofahs, brushes, and simply fingernails.

Pozzolana

pozzolanpozzolanic ashpozzolanic cement
A fine-grained version of pumice called pozzolan is used as an additive in cement and is mixed with lime to form a light-weight, smooth, plaster-like concrete.
Nowadays the definition of pozzolana encompasses any volcanic material (pumice or volcanic ash), predominantly composed of fine volcanic glass, that is used as a pozzolan.