Obsidian
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40 free Obsidian trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Obsidian is what happens when lava cools too fast to form crystals: a natural black glass that breaks to an edge finer than any steel blade. People have been chipping it into tools since the Stone Age, and it still turns up in operating theatres, video games and fantasy novels. This quiz turns the best obsidian fun facts into multiple-choice questions: how the rock forms and why it is not a true mineral, where the famous flows are, how ancient peoples traded it across continents, and the gods, weapons and mirrors it inspired. Every answer comes with a short explanation. It suits rock collectors, geology students, teachers planning an earth science lesson, and anyone who likes a surprising fact about a rock.
30 of 40 questions with answers and explanations. Play the quiz
Q 01In Game of Thrones, obsidian that can destroy White Walkers is better known by which name?
Dragonglass
Dragonglass is the Westeros name for obsidian, and Samwell Tarly proves its power in A Storm of Swords by killing one of the creatures with a dagger made of it.
Q 02Which Egyptian pharaoh's golden funerary mask has quartz eyes fitted with pupils of obsidian?
Tutankhamun
Tutankhamun's mask pairs its obsidian pupils with eyebrows and eye surrounds of blue lapis lazuli, all set into about ten kilograms of gold.
Q 03Where in the Pacific do giant stone statues have sockets made to hold white coral eyes with obsidian pupils?
Easter Island
Easter Island's moai kept the secret until 1979, when archaeologists pieced together broken white coral and realised the empty sockets were built to hold eyes.
Q 04In Minecraft, a frame of obsidian blocks becomes the portal to which dimension?
The Nether
The Nether is made mostly of lava, a fitting place to reach through a doorway of obsidian, since the real rock is itself born from lava.
Q 05Conquistadors reported obsidian-edged swords killing which animal with a single blow to the neck?
Horse
Horse and rider were both at risk: Bernal Díaz del Castillo described warriors slashing at a cavalryman's mare and cutting her head off at the neck.
Q 06John Dee is said to have used an Aztec obsidian mirror to summon spirits while advising which English queen?
Elizabeth I
Elizabeth I kept Dee as her court astronomer, and the mirror linked to him, an Aztec piece brought to Europe in the late 1520s, is now in a London museum.
Q 07Obsidian flakes to an edge far finer than steel, so surgeons have tested it in which tool?
Scalpels
Scalpels with obsidian blades can have a cutting edge only about three nanometres thick, but the glass is brittle and the blades break very easily.
Q 08Obsidian Cliff, quarried by Native Americans for some 12,000 years, stands in which US national park?
Yellowstone
Yellowstone's Obsidian Cliff formed from a thick lava flow about 180,000 years ago, and its roadside kiosk was the first wayside exhibit in the national park system.
Q 09Which name is given to small rounded obsidian pebbles, after a legend of grieving families in Arizona?
Apache tears
Apache tears take their name from a story in which outnumbered warriors chose death over defeat, and the tears of their families turned to stone where they fell.
Q 10Which frothy volcanic rock, light enough to float, is found alongside obsidian in the same lava flows?
Pumice
Pumice is a glass too, frothed by escaping gas like a freshly opened fizzy drink, so a single flow can be solid obsidian at its base and foam at the top.
Q 11What was the Aztec wooden sword edged with rows of razor-sharp obsidian blades called?
Macuahuitl
Macuahuitl means hand-wood in Nahuatl, and the weapon's glass edges were sharper than steel razors yet tended to shatter against Spanish armour.
Q 12Which Aztec god of the night sky and sorcery has a name usually translated as Smoking Mirror?
Tezcatlipoca
Tezcatlipoca is often shown with an obsidian mirror where one foot should be, a reminder of the creation myth in which he lost it to the earth monster Cipactli.
Q 13Which speckled countertop rock shares obsidian's chemistry but cooled slowly, deep underground, into large crystals?
Granite
Granite and obsidian can come from the same magma: left to cool slowly it grows visible crystals, but chilled fast at the surface it freezes into glass.
Q 21Which Roman author's Natural History says obsidian was first found in Ethiopia by a Roman traveller?
Pliny the Elder
Pliny the Elder named the finder Obsius, and the modern word rests on a copying slip that turned the Latin obsianus into obsidianus.
Q 22Obsidian from Pachuca in central Mexico was prized across Mesoamerica for which unusual colour?
Green
Green obsidian with a golden tint came from the Pachuca quarries, and a scraper made of it has turned up as far away as Oklahoma.
Q 23The Aztec goddess Itzpapalotl has a name usually translated as the obsidian form of which winged creature?
Butterfly
Butterfly sounds gentle, but Itzpapalotl was a fearsome warrior goddess, pictured with a skeletal head and wings tipped with stone blades.
Q 14Obsidian is born from cooling lava, which places it in which of the main families of rock?
Igneous
Igneous rocks form from molten material, yet obsidian rarely lasts: the glass slowly crystallises into ordinary stone, so little of it is older than the Miocene epoch.
Q 15Which lightweight white granules in potting soil are made by heating a rock that began as obsidian?
Perlite
Perlite swells to as much as 16 times its size when heated, puffing up so dramatically that Popular Mechanics called it volcanic popcorn in 1954.
Q 16Archaeologists date obsidian tools by measuring a thin rind that grows as the glass absorbs what?
Water
Water creeps into a freshly broken obsidian surface at a rate that can be measured, so the thickness of the rind works like a clock that started when the tool was chipped.
Q 17The oldest known manufactured mirrors, polished obsidian from around 6000 BCE, were found in which modern country?
Turkey
Turkey's Stone Age town of Çatalhöyük yielded the mirrors, and its people also chipped obsidian into blades, daggers and sickles.
Q 18Some of the earliest known obsidian tools, Stone Age handaxes, come from Kariandusi in which African country?
Kenya
Kenya's Kariandusi site sits on the edge of the Great Rift Valley, and its handaxes were probably made by Homo erectus, long before our own species appeared.
Q 19Obsidian carried more than 1,500 miles from the Rocky Mountains was buried in Hopewell mounds in which state?
Ohio
Ohio's Hopewell people buried hundreds of pounds of the volcanic glass in their mounds, and may have made the long journey west to fetch it themselves.
Q 20Apollo astronauts trained at Newberry Volcano, home of the hikeable Big Obsidian Flow, in which US state?
Oregon
Oregon's Big Obsidian Flow is only about 1,300 years old, the youngest lava on Newberry Volcano, and NASA sent crews there in the 1960s to practise reading volcanic terrain.
Q 24Stone Age sailors crossed the Aegean to collect obsidian from which Greek island, later famed for a Venus statue?
Milos
Milos obsidian reached a mainland cave around 13,000 BC, the earliest evidence of seafaring by modern humans in Greece.
Q 25Which glassy pebbles, now linked to meteorite impacts, were once thought to be obsidian erupted from the Moon?
Tektites
Tektites had a NASA scientist arguing for a lunar origin into the 1990s, but their chemistry shows they were melted from Earth's own crust.
Q 26What is the craft of striking flakes from obsidian or flint to shape blades and arrowheads called?
Knapping
Knapping was revived in the 20th century by experimenters such as Don Crabtree, who taught himself to copy ancient obsidian blades by studying the chips their makers left behind.
Q 27Which term describes the smooth, curved surfaces left when obsidian or thick glass breaks?
Conchoidal
Conchoidal fracture leaves ripples like the growth lines on a seashell, and it happens because glass has no natural planes to split along.
Q 28Obsidian is usually the glassy form of which pale volcanic rock, whose stiff lava piles up into domes?
Rhyolite
Rhyolite lava is extremely viscous, so atoms cannot shuffle into crystals before it chills, and a whole flow can set as natural glass.
Q 29Which compound, the main ingredient of ordinary window glass, makes up 70% or more of obsidian?
Silica
Silica makes lava thick and sticky, so its atoms struggle to line up into crystals before the flow freezes, which is why obsidian forms only from the most glass-prone lavas.
Q 30Which ancient Mexican city of the Pyramid of the Sun exported fine obsidian tools across Mesoamerica?
Teotihuacan
Teotihuacan had more than 100 obsidian workshops, and the trade has been seen as a key part of the city's rise to power.