The misidentification of travertine as alabaster and onyx is common in archaeological literature. Travertine is a variety of limestone, alabaster is a variety of gypsum, and onyx is a variety of quartz.

Travertine is the nonporous, banded variety of limestone that forms when calcite (calcium carbonate, CaCO3) precipitates from solution producing dripstone formations like stalactites and stalagmites in caves and around hot springs. The term onyx marble has also been used to describe travertine in geology (Klein and Hurlbut, 1985) and archaeology (Lothrop et al., 1959); however, travertine is the preferred term (Leighton and Pendexter, 1962) because travertine is neither onyx (microcrystalline quartz) nor marble (metamorphosed limestone). Artifacts composed of travertine (calcite) exhibit characteristic banding, have a hardness of 3 and a density of 2.71 g/cm3, and effervesce in cold, dilute hydrochloric acid. The reactivity of calcite to acids is responsible for the discolored, corroded surfaces of most artifacts composed of travertine. The prehistoric Maya carved containers out of travertine obtained from caves that occur throughout Belize, the lowlands of Guatemala, and the Yucatan Peninsula.

Deposits of alabaster, the granular, compact variety of gypsum (hydrated calcium sulfate, CaSO4 x 2 H2O) do not occur in Mesoamerica; therefore, alabaster was not available to prehistoric Mesoamerican Indians (de Borhegyi, 1952). Satin spar, the fibrous variety of gypsum, was used to a very limited extent by the prehistoric Maya. One small cylindrical container composed of satin spar is at the Department of Anthropology in Belmopan, Belize. I consider shaping and polishing such an artifact to be quite an accomplishment given the friable character of satin spar. Alabaster has a long history of use by Mediterranean cultures; however, many "alabaster" artifacts from this region are also composed of travertine. The varieties of gypsum have a hardness of 2 and a density of 2.32 g/cm3.

Questions regarding the sources of alabaster and the exchange of alabaster artifacts require positive identification of artifact mineralogy. The travertine and satin spar utilized by the prehistoric Maya were probably quarried from nearby deposits and were not exotic materials obtained from remote sources. Mediterranean cultures obtained alabaster and travertine from different localities since they form in different geologic settings. The misuse of the term alabaster can be avoided by including mineralogical analysis in archaeological surveys and artifact descriptions.

De Borhegyi, S.F., 1952, Travertine Vase in the Guatemala National Museum, American Antiquity, vol. 3, p. 254-256.

Klein, C., and Hurlbut, Jr., C.S., 1985, Manual of Mineralogy (after James D. Dana), 20th ed., John Wiley and Sons, N.Y.

Leighton, M.W., and Pendexter, C., 1962, Carbonate Rock Types, in Classification of Carbonate Rocks, Memoir 1, Ham, W.E., ed., American Association of Petroleum Geologists, p. 33-61.

Lothrop, S.K., Foshag, W.F., and Mahler, J., 1959, Robert Woods Bliss Collection, Pre-Columbian Art, Phaiden Press, London, England.