Pumice
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40 free Pumice trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Pumice is the odd one out among rocks. It is born in seconds, when gas-charged molten rock is thrown from a volcano and hardens around its own bubbles, and the result is a stone so light that whole fields of it can drift across an ocean. These questions gather the best fun facts about pumice in one place: how it forms and what sets it apart from its volcanic cousins, the famous eruptions that produced it, the rafts that carry plants and animals between islands, and the surprising jobs people have found for it over thousands of years, from building and grooming to gardening and laundry. The quiz suits curious players of any age, rock collectors, and students or teachers working through a geology or volcano unit. Every answer comes with a short explanation, so you finish with a fact worth repeating.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Which volcano's 1883 explosion left pumice rafts adrift, tree trunks and all, for up to 20 years?
Krakatoa
Krakatoa threw out so much pumice that in places the floating raft stood 1.5 metres above the waves. Ships reported huge fields of it for months afterwards.
Q 02Which Roman landmark did engineers lighten by adding more pumice to the concrete as they built higher?
Pantheon
The Pantheon's dome is still the world's largest unreinforced concrete dome, almost 2,000 years on. Light pumice and tufa at the very top keep its weight down.
Q 03Which clothing gets its faded, worn-in look from being tumbled with pumice stones in a rotating drum?
Denim jeans
Denim jeans are stone-washed with pumice, which also softens the stiff cloth. The catch is that each pair wears out sooner.
Q 04Which soft-furred pet rodent keeps clean by rolling in a bath of fine pumice dust a few times a week?
Chinchilla
A chinchilla should not bathe in water, because its fur can mat and grow mould. The animals take to their pumice dust baths by instinct.
Q 05Pumice was once called spuma maris in Latin because people believed it was hardened what?
Sea foam
Sea foam seemed a fair guess for a pale stone found bobbing on the waves. Around 80 BC the Romans also knew it as lapis spongiae, for its sponge-like holes.
Q 06In ancient Rome, powdered pumice was a gritty ingredient in which everyday hygiene product?
Toothpaste
Toothpaste with finely ground pumice has been sold in modern times too, because the grit strips plaque easily. It is too abrasive to use every day, though.
Q 07Which heavy-duty hand soap bar, first made in St. Louis in 1893, contains ground pumice?
Lava
Lava takes its name from the ground volcanic pumice in every bar. The WD-40 Company, better known for its spray lubricant, bought the brand in 1999.
Q 08Astrobiologists have proposed drifting pumice rafts as an ideal setting for which event on early Earth?
The origin of life
The origin of life needs a busy surface, and pumice rafts have the highest surface-area-to-volume ratio of any rock type. They also drift for years, soaking up useful chemicals.
Q 09Which Roman city did pumice from Vesuvius rain on in 79 AD, collapsing roofs before the deadly surges?
Pompeii
Pompeii lay downwind, so the pumice fell there while upwind Herculaneum was spared at first. The stones piled up until roofs gave way.
Q 10A pumice raft mistaken for land may explain which phantom isle near New Caledonia, mapped from 1876?
Sandy Island
Sandy Island stayed on charts, Google Maps included, until an Australian research ship sailed through the spot in 2012. The whaler Velocity may have logged a pumice raft as dry land.
Q 11Lipari holds pale pumice and which dark, glassy rock that Stone Age toolmakers traded as far as Croatia?
Obsidian
Obsidian from Lipari was worked into fine bladelets by the late Neolithic and traded to Sicily and the Po valley. The island is covered in both rocks.
Q 12Which darker, denser volcanic rock, also known as cinder, usually sinks in water where pumice floats?
Scoria
Scoria has bigger bubbles with thicker walls than pumice, which makes it heavier. It builds the steep little cinder cones found on many volcanic fields.
Q 13A pumice raft covering 26,000 square kilometres was spotted in 2012 by which Pacific country's navy?
New Zealand
New Zealand's navy met the raft near Raoul Island, with pumice blocks poking 60 centimetres above the surface. Its possible source, the Havre Seamount, had erupted unseen on the seabed weeks earlier.
Q 21Scribes rubbed pumice powder into which writing surface while it was wet and stretched on its frame?
Parchment
Parchment took ink more deeply once pumice powder had smoothed its flesh side. Early bookmakers also used the stone to finish leather bindings.
Q 22Ancient Egyptians used pumice stones, razors and creams to remove what, partly to control lice?
Body hair
Body hair was removed all over in ancient Egypt, as a form of ritual purification as well as pest control.
Q 23During a salon pedicure, a pumice stone rubs dead skin and which hardened patches off the feet?
Calluses
Calluses were being smoothed with pumice in ancient China, where the stones also kept fingernails groomed.
Q 14Pumice rafts from undersea eruptions near Tonga in 1979, 1984 and 2006 all drifted west to which nation?
Fiji
Fiji lies about 350 kilometres west of the Tongan volcano behind the 2006 raft. Some of the earlier rafts were reportedly 30 kilometres wide.
Q 15Corals have crossed the Pacific from Tonga on drifting pumice rafts to reach which World Heritage site?
Great Barrier Reef
The Great Barrier Reef is a long ride away: pumice tracked after one Tongan eruption drifted more than 3,000 kilometres west. Biologists think plants and animals hop between islands the same way.
Q 16What sudden change makes gas fizz out of rising magma to form pumice, as when a soda bottle is opened?
A drop in pressure
A drop in pressure frees the dissolved gas, and rapid cooling then freezes the bubbles in place before they can escape. Both have to happen at once.
Q 17Which Philippine volcano's 1991 eruption, the 20th century's second-largest, rained white pumice?
Mount Pinatubo
Mount Pinatubo emptied so much magma that its summit collapsed into a hollow. The haze it threw into the sky cooled the whole planet by about half a degree Celsius.
Q 18Which Cascade Range volcano sent out flows of glowing pumice bombs in a 1980 eruption that killed 57?
St. Helens
St. Helens produced two kinds of pumice in 1980: a white type that is about 86 percent bubbles and a denser grey type. It remains the costliest eruption in US history.
Q 19What are towering, pumice-rich eruptions like Vesuvius in 79 AD called, in honour of a Roman eyewitness?
Plinian
Plinian eruptions are named for Pliny the Younger, who described Vesuvius in a letter after the eruption killed his uncle. They punch columns of debris into the stratosphere.
Q 20On which Greek island are houses extended with rooms dug sideways into pumice, cool all summer?
Santorini
Santorini closed its pumice quarries in 1986 to protect its caldera. The air-filled rock insulates so well that the dug-out rooms stay warm in winter too.
Q 24Ancient Chinese medicine added ground pumice, mica and fossil bones to which drink to calm the spirit?
Tea
Tea laced with ground pumice was prescribed for dizziness, nausea, insomnia and anxiety. Healers believed that swallowing powdered rock could soften lumps inside the patient.
Q 25Around 1680, an English naturalist noted that pumice powder was used to bring on which reflex?
Sneezing
Sneezing was one of many odd jobs given to pumice by early doctors. In the 18th century, pumice ground as fine as sugar went into remedies for ulcers of the skin and eye.
Q 26A pumice stone on a handle is a household tool for scrubbing limescale rings off fixtures made of what?
Porcelain
Porcelain bathroom fixtures can be scrubbed with a pumice stone, which also shifts rust and hard water rings.
Q 27Gardeners mix pumice into potting soil to suit cacti and which other drought-hardy plants?
Succulents
Succulents thrive because pumice lets water and gases pass through its pores while storing nutrients in the tiny holes. It does not rot, and it does not attract fungi or insects.
Q 28Pumice is the gritty abrasive mixed into the rubber of which everyday desk item, often coloured pink?
Erasers
Erasers owe an older debt to pumice too: before rubber, writers scraped ink mistakes away with bits of the rough stone. The first widely sold rubber ones appeared in 1770.
Q 29Pozzolana, the volcanic ash and pumice Romans mixed with lime, takes its name from a town near which city?
Naples
Naples lies close to Pozzuoli, whose volcanic sand Vitruvius recommended for mortar around 25 BC. He gave a separate recipe for work under water.
Q 30Pumice-rich flows from the 1912 Novarupta eruption filled which US state's Valley of Ten Thousand Smokes?
Alaska
Alaska's Novarupta eruption was the largest of the 20th century. Explorer Robert Griggs named the valley in 1916 for the thousands of steam vents rising from the fresh deposits.