Rock
Tezontle
Tezontle
The red stone of Mexico City: a light volcanic scoria used from Aztec temples to Baroque palaces, well suited to the city's sinking lake bed.
Also known as: Tezontle volcanic scoria · Tetzontli (Nahuatl)
- Popularly: Natural stone (building and decor)
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In short
Tezontle is a red, porous and highly oxidised volcanic rock used widely in Mexico; it is a kind of volcanic cinder that geologists call scoria. It gets its red colour from iron oxide and is very light because of the holes left by gas bubbles. It has been used in building for at least 20 centuries: at Teotihuacan, in the temples of the Aztec capital Tenochtitlan and on the colonial façades of Mexico City. In 2024 the International Union of Geological Sciences (IUGS) named it a Global Heritage Stone.
Photos
How does it form?
Tezontle formed in small volcanoes in the eastern Trans-Mexican Volcanic Belt that have been active from the Pliocene to the present (Holocene). Most of these volcanoes are cinder cones built by a single eruption. During an eruption, gas-filled lumps of basaltic lava are thrown into the air and cool quickly, and the gas bubbles inside them remain as holes. The resulting porous, glassy rock is called scoria (volcanic cinder).
Tezontle’s red colour comes from iron in the hot cinder reacting with air and oxidising. Its main sources are the Chichinautzin volcanic field south of Mexico City and the Apan-Tecocomulco field to the northeast, both around the Anáhuac basin that once held Lake Texcoco.
What is it used for?
- Building and façade stone: It was used at Teotihuacan in the 1st–7th centuries AD and on a massive scale in the temples of Tenochtitlan from the 14th century. In colonial times, cut red tezontle became the hallmark of Baroque façades in Mexico City.
- Lightweight concrete and plaster: It is mixed into concrete for lightweight blocks and with cement for stucco.
- Roads and gardens: Crushed tezontle is used as the top layer of unpaved roads and as a substrate in gardens, cactus gardens and aquariums.
- Ovens and steam baths: Because it holds heat, it is also used to build bread ovens and traditional temazcal steam baths.
Where can you see it?
Tezontle is taken from cinder cones around the Valley of Mexico. In the historic centre of Mexico City it can be seen on buildings such as the Metropolitan Cathedral, the National Palace, the Monte de Piedad and the Church of San Bernardo, at the Templo Mayor ruins and at Teotihuacan. The historic centre of Mexico City and Teotihuacan are UNESCO World Heritage sites.
What determines its value?
As a building stone its value lies in its lightness, workability and warm red colour; that lightness matters especially for building on soft lake ground. Crushed tezontle is cheap and sold in bulk for unpaved roads, gardens and lightweight concrete blocks. For restoring historic buildings, stone of the same colour and texture is also prized.
This information is educational, not buying, selling or investment advice. Value varies enormously with quality and treatment.
How to recognise it
- 1
Dark or brick red; some kinds are blackish or greyish.
- 2
Full of holes like a sponge, and much lighter in the hand than you would expect.
- 3
A broken surface is rough and glassy, with angular volcanic fragments that look welded together.
Myths and misconceptions
MythTezontle is a brick that has been dyed or fired red.
FactTezontle is a natural volcanic rock. Its red colour comes from the oxidation of iron in the volcanic scoria, and it comes out of the quarry this colour.
Did you know?
Its name comes from the Nahuatl tetzontli, made of tetl, “stone”, and tzontli, “hair”.
Mexico City stands on the soft, water-saturated bed of a drained lake. Light tezontle was favoured because it helps slow buildings from sinking into this ground.
The façades of historic buildings such as the Metropolitan Cathedral, the National Palace and the Monte de Piedad in Mexico City are faced with cut tezontle.
Where is it found?
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- Sierra Chichinautzin volcanic field, south of Mexico City, Mexico · Major depositA field of small, single-eruption cinder cones in the Trans-Mexican Volcanic Belt; one of the two main sources of tezontle.
- Apan-Tecocomulco volcanic field, Hidalgo, Mexico · Major depositThe cinder-cone field that is the second main source of tezontle. The point marks the town of Apan.
- Teotihuacan, State of Mexico, Mexico · Historic sourceThe earliest documented use of tezontle (1st–7th centuries AD) is in the buildings of this ancient city.
- Templo Mayor and the historic centre, Mexico City, Mexico · Historic sourceFrom the 14th century the temples of the Aztec capital Tenochtitlan were built largely of tezontle, and the façades of 17th–18th-century colonial and Baroque buildings also carry it.
Locations are approximate to protect sites. Red dots mark places in Türkiye. Open in the big map →
Frequently asked questions
What is tezontle?
Tezontle is a red, porous and highly oxidised volcanic rock used widely in Mexico; it is a kind of volcanic cinder that geologists call scoria. It gets its red colour from iron oxide and is very light because of the holes left by gas bubbles. It has been used in building for at least 20 centuries: at Teotihuacan, in the temples of the Aztec capital Tenochtitlan and on the colonial façades of Mexico City. In 2024 the International Union of Geological Sciences (IUGS) named it a Global Heritage Stone.
Why is tezontle so light?
Tezontle forms when gas-filled lumps of lava thrown from a volcano cool quickly. The escaping gas bubbles leave countless holes inside the stone, so tezontle is very porous and light. That is why it was favoured as a building stone on Mexico City's soft lake bed.
What is tezontle used for?
Building and façade stone: It was used at Teotihuacan in the 1st–7th centuries AD and on a massive scale in the temples of Tenochtitlan from the 14th century. In colonial times, cut red tezontle became the hallmark of Baroque façades in Mexico City. Lightweight concrete and plaster: It is mixed into concrete for lightweight blocks and with cement for stucco. Roads and gardens: Crushed tezontle is used as the top layer of unpaved roads and as a substrate in gardens, cactus gardens and aquariums.
How hard is tezontle?
It has a hardness of 5–6 on the Mohs scale. It can scratch glass; a steel knife scratches it only with difficulty. Its specific gravity is 1–2 g/cm³.
Where is tezontle found?
Its best-known localities: Sierra Chichinautzin volcanic field, south of Mexico City, Mexico; Apan-Tecocomulco volcanic field, Hidalgo, Mexico; Teotihuacan, State of Mexico, Mexico; Templo Mayor and the historic centre, Mexico City, Mexico.
How can you tell if tezontle is real?
Dark or brick red; some kinds are blackish or greyish. Full of holes like a sponge, and much lighter in the hand than you would expect. A broken surface is rough and glassy, with angular volcanic fragments that look welded together.
Is tezontle valuable?
On the “street to diamond” value ladder it sits on step 3 of nine: Building and industrial stone. As a building stone its value lies in its lightness, workability and warm red colour; that lightness matters especially for building on soft lake ground. Crushed tezontle is cheap and sold in bulk for unpaved roads, gardens and lightweight concrete blocks. For restoring historic buildings, stone of the same colour and texture is also prized.
Sources
- Tezontle · Wikipedia
- Tezontle volcanic scoria (Global Heritage Stone) · IUGS Subcommission on Heritage Stones, 2024
- Tezontle · Wikipedia (es)
- Natural building stones of Mexico–Tenochtitlán: their use, weathering and rock properties at the Templo Mayor, Palace Heras Soto and the Metropolitan Cathedral · Environmental Earth Sciences (Springer), 2011
- Scoria · Wikipedia
- Sierra Chichinautzin · Wikipedia
- Teotihuacan · Wikipedia
- Templo Mayor · Wikipedia
External links
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