Since the 1970s, researchers have attempted to pin down the source of turquoise--that lovely blue-green mineral aka hydrated copper aluminum phosphate, cherished and used as jewelry and inlay by so many ancient societies.
The usual method for such studies is called trace element analysis, essentially breaking down the mineral to its component parts and comparing the various ratios to quarry sites. Unfortunately, in this case, the component parts vary too much within mines and artifacts to allow the precise source identification.
However, according to a new paper in the May 2008 issue of the Journal of Archaeological Science, researcher Sharon Hull and associates have identified the source of turquoise artifacts from the American southwest as having come from specific mines in the Cerillos Hills of central New Mexico. Using stable isotopes of hydrogen and copper, Hull et al. have been able to characterize mines in the Cerillos Hills and then compare those ratios to raw materials from those mines, and finally to artifacts of previously unknown provenance.
Whether the technique will be able to be extended to other mines and artifacts around the world remains to be seen, but the method does seem to show promise.
Sources
Read the glossary entry on Turquoise for more information on turquoise in the Americas and the rest of the world.
Hull, Sharon, Mostafa Fayek, Frances Joan Mathien, Phillip Shelley, and Kathy Roler Durand. (2008). A new approach to determining the geological provenance of turquoise artifacts using hydrogen and copper stable isotopes. Journal of Archaeological Science, 35(5), 1355-1369. DOI: 10.1016/j.jas.2007.10.001
Comments
I learned about sourcing turquoise when I worked in the oilfields of New Mexico & Utah, & by speaking to a Jeweler in Durango Colorado, who is in possesion of some real nice specimens of white turquoise from Arizona.
I know where there is some very nice Apple-Jade in Wyoming.
And now, for something completely different . . .
Several years ago the Editor of World Oil magazine published an article that spoke about geology students exploring the usefulness of Iridium in a sample to extrapolate the date of stuff, instead of Carbon 14.
http://www.worldoil.com
Really? That sounds interesting. Do you happen to have a citation?
Kris
Thanks for writing such a concise article. I’ll be able to share this with my students w/out having to translate any techno-speak !
I just passed this on to my wife Sue Scott, who has been working at tracing turquoise in Mesoamerica to its sources. That has turned out to be quite a difficult and trying effort and this new technique may help.