Lander Blue and one Chinese
Mike Ryan- There has been a great deal of interest in the X Ray Florescence (XRF) method of testing turquoise for mine origin through analyzing the chemistry of the component elements. I have provided baseline samples from the Callais Collection to begin the database for comparison. This is growing as both collectors and those in the trade recognize the value of testing and are submitting turquoise for analyses. In this article Neil Ray explains more of the testing process and describes the analyses of a recent test on several samples of what had been identified as Lander Blue. Neil's explanation is a bit technical but that will happen when the science is accurate and detailed.
Neil Ray-P3M is software that was developed over the course of 10 years of research, by analyzing and researching the chemistry of thousands of rock types, as well as citing over 50 peer reviewed professional publications. The analysis of turquoise has only recently been added over the course of the past year. P3M stands for petromaster, paymaster, and provenance master. A full P3M report will provide an extreme amount of detail on any rock or mineral type, which for our focus today is turquoise. A P3M report cost $65/specimen and it is well noted that a typical XRF analysis only cost around $30 to $40 each. However, the typical xrf analysis will only provide the chemical analysis, with no mineralogy determinations whatsoever. Additionally, XRF analysis typically provides the analysis of magnesium through uranium, sometimes sodium, but certainly nothing lighter than sodium. Petromaster uses a series of calculations to calculate sodium and lithium, which knowledge of lithium concentrations is very valuable to the mining exploration sector. Petromaster uses the chemical analysis of the rock to determine the mineralogy of almost 100 different mineral species. This is extremely beneficial to both the seasoned mineral collector and the geological research scientist alike. Mineralogy is certainly one of the most valuable aspects of Petromaster, as to arrive at mineralogy, a different laboratory analysis is required; xray diffraction (XRD). Unlike XRF, XRD is destructive and requires the specimen to be ground and passed through a fine mesh sieve, the cost also approaches anywhere from $50 to $200 per sample. Though turquoise often has a very simple mineralogy of quartz, feldspar, pyrite, clay etc, additional mineral species become more critical in the understanding of igneous and metamorphic rocks. Nevertheless, the small amounts of different sulfides provide a description of formation and unique mineralogy that we will see when we examine analyses of Lander Blue. Old time spiderweb KIngman has elevated amounts of molybdenum, which is interesting in that there is little to no molybdenite, all the molybdenum is substituted for copper in the structure of the turquoise and not in sulfide form as expected. Examples of this rare turquoise are available from Mike Ryan on his website. Petromaster also has the unique ability to calculate the porosity and permeability of the sample, as well as the pressure and temperature of which it formed. Though it may seem apparent that this information is only beneficial to the scientist, it is also extremely useful in comparing and verifying origin by pressure/temperature of other mines and seeing how it compares to each other. Additionally, porosity is useful to the average turquoise enthusiast, as it provides an indication of surface pitting on samples, which distract from the overall finish and durability on cabochons. The second part of P3M is Paymaster, which I will not get into too much, as it was developed for the petroleum industry to calculate how much oil and gas reserves are available in the rock and the quality of the oil being generated. The one everyone is interested in specifically is Provenance Master, which uses the trace element chemistry of turquoise to determine the likely source of mine origin, as well as the grade. Up to four probabilities are provided for each specimen, if two or three probabilities are duplicated then there is an extreme likeliness that the specimen in question is from the mine origin provided. Provenance Master uses trace element chemistry to determine the grade, based on the R2 grading scale developed by Mike Ryan, which relies on the three most important concepts of turquoise grading: color, hardness, and matrix. An assigned origin probability is determined by a series of ternary diagrams, which are particularly helpful when comparing three variables to each other. With the complexity of such an analysis, it is certain that mines will overlap and outliers will be present from mine to mine, as such it is important to examine all five ternary diagrams and Provenance Master utilizes additional trace element allocations that are unique to each mine to up the accuracy and confidence of the origin provided. The PT diagram that follows is also useful in that it provides a graphical representation of all the turquoise in Provenance Master's database by pressure/temperature paths. As with the ternary diagrams, some specimens may overlap other mines, however when used in conjunction with the ternary plots the origin confidence level is greatly increased. Mike Ryan provided ten cabochons of potential Lander Blue, let's examine the results.P3M can provide up to 5 specimens on a single report, thus the Lander collection was divided up into two separate reports (A-E) and (F-J). Page 1 provides a photograph of the specimens and a reference number, which will be used throughout the report. Lander Blue has a unique chemistry, which means little variation, and this unique chemistry attains that most Lander Blue is very high grade too gem grade. Perhaps the most unique aspect to Lander Blue is the uranium concentration, which is over 25 ppm (0.0025%) and holds for all the specimens of known Lander that I have analyzed. Though high uranium doesn't guarantee that the specimen is Lander, as some mines also have high uranium, such as Hubei. Though it can be safe to say that if the specimen has uranium concentrations that are less than 20 ppm, then the specimen is not Lander Blue. Specimens A through E are all guaranteed authentic Lander Blue, specimen C is particularly interesting, as it contains a considerable amount of tin, as the mineral cassiterite. Cassiterite is likely found in the matrix, as this specimen shows superb webbing and is gem grade. When we examine the ternary diagrams, you will note that Lander Blue is depleted in silver and most fall to the bottom of the triangle (the closer to the triangle's apex, the higher the concentration). The same can be said with depletion of iron in ternary #2, ternary #3 is interesting as it shows a wide variation in molybdenum, chromium, and lead. Specimens A and B are more enriched in lead and they also visually have a different spiderweb pattern then that of specimens C, D, & E; again, both are gem grade Lander Blue. From ternary #4 it can be seen that specimens A and B are also depleted in antimony. All five specimens have higher strontium, which means a lower RB/Sr ratio and plotting at the bottom of the triangle in ternary 5. Even though specimens A and B appear slightly different, they still have a characteristic trace element pattern to confidently identify them as Lander Blue. Specimens F through J also show the same trend in chemistry on the ternary diagrams, except for specimen I, which CAN NOT be classified as Lander Blue. Specimen I has only 17 ppm uranium and after close examination, we can see from ternary #2 that it is lower in zinc than the rest of the specimens. Additionally, it can be seen on ternary #4 that it is slightly elevated in bismuth. This deviation is enough to indicate that specimen I is Hubei. Though it may still be Lander and represent a significant outlier from the Lander Blue dataset, however a Chinese origin is highly likely. On the remaining page you can see that all specimens generally follow the PT gradient #6 and specimen I has the highest pressure out of all ten that were analyzed. I hope you find this information useful and you are ready to analyze your turquoise that has been tucked away to find out both where it originates from and its valuation by grade.
For anyone interested in having turquoise tested Neil may be reached at West Texas Analytical Lab, Pampa TX. His phone is 580 977-6951.
Santa Fe
July 2024
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