Turquoise, sourcing

In the case of turquoise the author and Weigand are engaged in an open-ended project which seeks to analyze specimens taken from literally every existing and accessible turquoise source used aboriginally in North America. Early research by Sigleo likewise utilized NAA There is also another very extensive and detailed analytical study of turquoise recently published by Ruppert giving results for both... 

Weigand PC, Harbottle G, Sayre EV (1977) Turquoise Sources and Source Analysis Meso-... 

Figure 3.1. Different types of environments encountered by ions (hexafluorophosfate in green, l-butylS-methylimidazolium in red) and acetonitrile (blue) in nanoporous carbon electrodes (in turquoise) (source Nature Communications). For a color version of the figure, see WWW. iste.co. uk / tarascon / storage.zip...

The use of trace element analysis to determine the provenance of archaeological materials has expanded rapidly in the last decade. It is now a well-established technique for the identification of obsidian source deposits (J), and is nearly as established for turquoise (2), steatite (3), and some ceramic materials (4). Native copper has received much less attention. Friedman et al. (5), Fields et al. (6), and Bowman et al. (7) used trace element analyses to determine the type of geological ore from which copper was extracted. However, only our efforts (8) and the work of Goad and Noakes (9) have focused on collecting and analyzing native copper from all potential deposits of a given region to provide a data base for statistical comparison with artifact trace element compositions. 

Artide/Source Dark Yellow Can Go Indigo Clarity/Readability Green Development Blue Essay Structure Orange Metadiscourse/Transitions Plum Paragraphs Turquoise Points Teal... 

Of great use in such investigations are artifacts or materials that come from a known location. It is in this area that archaeological chemistry has made an enormous contribution. There are many cases of such movement in exotic materials, often in the form of rare stones or minerals. There were no natural sources of turquoise in ancient Mexico, for example, but tins beautiful blue-green stone was imported from the present state of New Mexico and used in the costumes and jeweliy of the elite in Aztec Mexico.. Archaeological chemistry had documented the sources of turquoise in the southwestern and found objects from Mexico that clearly came from those quarries. This example is discussed in more detail in Chap. 8, Case Studies. 

He then examines some of the evidence regarding the validity of these assumptions. I might add parenthetically that in my own laboratory the analysis of a large munber of specimens of turquoise, a copj r phosphate mineral, which had been obtained from known mining areas, has demonstrated that Assumption (1) of Craddock s paper is true only in selected instances. Our analysis of other copper minerals like malachite also showed great trace element variance within a given source in several cases. 

North and South American source areas. In our work NAA is used, while Ruppert employed an automated electron microprobe. A data bank for turquoise exists, based on our work, at Brookhaven National Laboratory. 

Turquoise was extensively used in several of the ancient Me american civilizations, the Toltec, Aztec and Maya, in the construction of mo ic. Fig. 7 is one of several turquoise mosaic masks in the Ethnographic Collections of the British Museum One of the purposes of the development of a turquoise analytical data bank is to relate the turquoise used in Mesoamerica to their source areas, some of whidi were located in the southwestern United States (Fig. 8) The named areas in Fig. 8 refer to sites important in mining, processing or trade in PreColumbian turquoise. Strong relationships have been shown to exist between turquoise used in the Hohokam culture (7 in Fig. 8) and Chaco Canyon (site 6), by means of NAA. 

Fig. 3.24 Interferograms recorded for the pyramid test scene for baseline separations from 30 to 80 mm with baseline steps of 10 mm. Purple, yellow, black, dark blue and green correspond to sources 5,6,7,8 and 9 fiom Fig. 3.23, respectively. Turquoise corresponds to the reference source 1 and is overlapping with the interferogram corresponding to the reference source 2 (red). Light green corresponds to the reference source 3 and is overlapping with the interferogram corresponding to the reference source 4 (blue)...

As LA-MC-ICP-MS becomes more accessible, provenance studies may begin to combine elemental and isotopic characterization. Some time ago, Stos-Gale [114] suggested that metal provenance studies could be based on combined lead isotope and trace element analyses, and the same kind of combined approach would seem desirable in the case of turquoise as well as other, seldom analyzed materials such as ceramic glazes. Cooper et al. [115] combined trace element and LA-MC-ICP-MS lead isotope analysis of native copper from North America, but found that the lead isotopes were of little use in source discrimination. 

Ammonium Vanadate. NH4VO3, used as a source of vanadium in ceramic pigments, e.g. tin-vanadium yellow, zirconium vanadium yellow and turquoise, etc. 

These are not tiie major-element glass chemistries of the turquoise blue beads, royal blue beads, or the low-K black beads, but may reflect source glasses for white, red, and high-K black beads. 

Phosphates and sulfites are less common, although phosphates may be important sources of phosphorus in the form of fertihzer. Turquoise is a phosphate of copper, and is used as a gem stone. 

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