Art & Art History ETDs

Publication Date

Fall 11-6-2018


Blue and blue-green ceramic colorants are an uncommon occurrence in the ancient Americas. This paper explores blue and blue-green post-fire colorants used by the coastal Tolita-Tumaco culture of ancient coastal Ecuador and Colombia through compositional testing and cross-cultural comparison. Using X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, one sample each of blue and blue-green colorants were tested to identify the mineral composition present. Though the colorants were thought to likely originate from copper carbonates like azurite or malachite, or perhaps even similar to other Mesoamerican pigments like Maya Blue, the blue-green pigment, collected at La Tolita, was determined to be either celadonite or glauconite. No mineralogical component responsible for the blue colorant, from a site along the Rio Mataje, could be determined. Cross-cultural comparison provides insight on how ancient coastal Ecuadorian groups used these colorants and exemplifies the innovative nature behind their creation.



Document Type


Degree Name

Art History

Level of Degree


Department Name

UNM Department of Art and Art History

First Committee Member (Chair)

Dr. Margaret Jackson

Second Committee Member

Dr. Joyce Szabo

Third Committee Member

Aaron Fry


Tolita-Tumaco; blue; colorant; celadonite; glauconite; ceramic