Material: basalt

As stated previously, the statue is carved from basalt. Primary sources on basalt are limited; however, Bernardino de Sahagún provides a brief description in his Florentine Codex – in Volume 11, Chapter 11, Paragraph 7, titled “Metlatetl: Stones from which metates are made.” (1) The word is a compound of “metl” meaning maguey, and “tetl” meaning stone. This etymology alludes to the household/kitchen activity of maguey grinding, for which basalt was used (2). This is explored later on. Sahagún goes on to describe the stone as “black, dark … hard, very hard … it is solid, round, wide; asperous, scabrous, unpleasing, blemished. It is [material] which can be fashioned well, worked pecked, smoothed, abraded, sculpted.” (3) Some of these adjectives help describe the visual properties of basalt statues, specifically the Cihuateotl sculpture from the Native American Museum of New York.

Visual properties

By observing the visual properties of basalt, one can gain a better understanding of why Sahagún’s description is listed as solid, dark, hard, wide, asperous, scabrous, unpleasing, and blemished. The rapid formation of small crystals (less than 1mm) as the lava cools results in basalt’s fine-grained texture (4). The texture of the basalt is dependent on the rate at which the lava cools and hardens. If the lava cools quickly at a more rapid rate, volcanic glass may form within the structure of basalt. Volcanic glass is commonly referred to as obsidian and on its own has a lustrous, seemingly polished finish that results from the minuscule size of the crystal structure. Therefore, when volcanic glass forms witin the structure of basalt, a smoother, aphanitic texture is created on the surface (5). However, if the lava cools and hardens at a slower rate, the rock will develop small vesicles that fill with volcanic gas. As the rock ages, the gas dissipates leaving empty cavities behind (6). These cavities can be seen with the naked eye, which coincides with the “asperous” and “scabrous” adjectives found in Sahagún’s description. Furthermore, the dark, or black, color of basalt is a result of two things: the structure of the crystals and the minerals containing iron. The crystals are not visible to the naked eye, which is why the tone of the rock is fairly even. The black hue is a result of the iron-rich minerals pyroxene and magnetite (7). A physical property of iron is its shiny greyish color. (8). Furthermore, plagioclase, a silicate mineral that has a grey tone, can also be found in the igneous rock further deepening the hue of basalt (9). Due to the formation process of basalt, it is often called volcanic rock. The connection between volcanoes and the Aztecs is explored later.

Having addressed the terms Sahagún used to physically describe Basalt, we can turn our attention to his two subjective adjectives: “unpleasing” and “blemished.” When considering why the volcanic rock would be described in this manner, one could conclude that Sahagún would have rarely seen the rock in an uncarved and undecorated state. He would have more frequently come across the rock after it’s been covered in plaster and/or paint. To describe the rock as negative and flawed suggests that his perspective was shaped by how frequently he saw the rock in its natural state compared to its embellished state.

Aztec use of basalt

Basalt was a prominent material in Aztec and Mexica society. Michael E. Smith discusses basalt in his book The Aztecs. He defines it as “a hard and porous volcanic rock readily available in the Otumba region” (10). Otumba is located just less than 60 kilometers (40 miles) from modern day Mexico City, that is, from Tenochtitlan. It is likely that basalt stone was sourced from Otumba by the Mexica and dispersed throughout the empire to different workshops or artisans. “The waste flakes production tools that indicate basalt working were found at a few scattered locations within the city.” (11). This is further discussed by Thomas Charlton and others in “Aztec Craft Production and Specialization: Archaeological Evidence from the City-State of Otumba.” They describe the location and degree of specialization of basalt craft production in the Valley of Mexico. The authors provide a map of the Otumba region, locating the main basalt quarry, but state that basalt sources and industries were widely spread around the city. They note the basalt industry was household based. (12).

Once the basalt was acquired it “was worked into both domestic implements (such as manos and metates for grinding corn) and industrial tools (scrapers for loosening the fibers from maguey leaves and polishers for finishing lapidary products).” (13). This confirms the connection between basalt and the stone Sahagún calls Metlatetl. Overall, basalt seems to have been abundantly available and widely used. Beyond these household functions, the stone was also evidently used for works of art. Richard Townsend’s survey book The Aztecs highlights this: “Aztec craftsmen were employed by the state to make colossal basalt sculptures. Such figures as the great Coatlicue and the disk of Coyolxauhqui are examples of the Aztec genius for carving in high relief” (14). He explains that Aztec artists rarely worked on “liberating figures from the block of stone” like the contemporaneous Mediterranean artists, but toward the early 1500s some examples of this appear. Nevertheless, the signature format of basalt statutory is in bas relief carved into shaped stone.

The Significance of Basalt

To complete the discussion on basalt, it is important to consider the significance of this material – why the Aztecs chose basalt to carve statues such as this Cihuateotl sculpture. The evident reason is functionality. From the discussion so far, basalt was clearly a popular material and artists would be extremely familiar with the techniques of carving the stone. Furthermore, the abundant quantity made it highly accessible, and probably cheap. Lastly, given basalt is formed by small crystals, its composition is solid and therefore proves very durable.

Furthermore, the Mexica artist could have felt a connection between the medium and the subject. There is a precedent for this reasoning in Aztec art, given that artists of codices had a connection between the source of the pigment and the image on the page. (15). Applying this logic to basalt stones, Mary Ellen Millen suggests the volcanic rock “ has an inherent stoniness and roughness that long seemed appropriate to its subject matter, particularly the practice of human sacrifice” (16). Furthering this point, John Pohl and Claire Lyons argue that the usage of basalt might “represent anthropomorphic manifestation of the volcanoes that ring the Valley of Mexico” (17). However, attributing significance to this material is not without hurdles; a complication arises when one considers that “virtually all sculpture was plastered and painted with a vivid palette of primary colors” (18). Hence, the basalt itself would not be visible. This suggests basalt was chosen primarily for its functional purposes, mentioned above. Remembering that most basalt was hidden behind plaster and paint might explain the scarcity of description in primary sources and Sahagún’s limited description of basalt as a material used in household items – and not art.


Text and research collaborated on by Nicole Jordan, Delfina Pattacini, and Peter Vergara. 



  1. Sahagún, Florentine Codex, Vol. 11, Ch. 11, Par. 7
  2. Smith, The Aztecs, 105
  3. Sahagún, Florentine Codex, Vol. 11, Ch. 11, Par. 7
  4. Yoder, Origins of Basalt
  5. Le Maitre, "Igneous Rocks"
  6. Le Maitre, "Igneous Rocks"
  7. Le Maitre, "Igneous Rocks"
  8. "Visual Periodic Table of Elements." Royal Society of Chemistry. 2017.
  9. Le Maitre, "Igneous Rocks"
  10. Smith, The Aztecs, 105
  11. Smith, The Aztecs, 105
  12. Charlton et. al., 104-105
  13. Smith, The Aztecs, 105
  14. Townsend, The Aztecs, 183
  15. Magaloni, The Colors of the New World
  16. Miller, "Pre-Columbian Art of Mexico..."
  17. Pohl and Lyons, The Aztec Pantheon..., 34
  18. Pohl and Lyons, The Aztec Pantheon..., 34