Hi Turquoise People,
I thought it would be helpful if I started a new topic, as well as elaborated a little on what I wrote previously https://forum.turquoisepeople.com/t/1800s-gold-charm-photo-bracelet/13529/6?u=kaliko. There’s a lot here; I hope you find it helpful and insightful.
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There are a number of ways to determine the composition of precious metals and gems. Many jewelry and coin/precious metal stores have portable hand-held XRF (X-ray Fluorescence) analyzers. It takes a couple of seconds to do the test. [Some places may do it for free.]
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Unlike a number of other methods (such as acid etching, filing, or other physical removal techniques) for determining silver, gold and other chemical compositions, XRF analysis is non-destructive.
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This equipment is very accurate in determining the chemical (atomic) composition for most elements in the periodic table. The manufactures of these analyzers recommend periodic maintenance and calibration.
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XRF analysis was discovered over 100 years ago; it required fairly large equipment. Portable hand-held XRF analyzers were invented in ~2008, and that was a big breakthrough for much broader use. XRF is used for analyzing: 1) Precious metals [including part per million (ppm) detection of platinum, palladium, iridium, rhodium, etc. during gold jewelry reprocessing], 2) Diamonds, rubies, emeralds, sapphires (vs. CZs), and the ppm trace elements in natural gemstones showing that each one (or geological area mine) is unique, 3) Geology and Mining (including a few rock hunters;-), 4) Industrial metal fabrication, 5) Environmental, etc.
Here’s several links that you may find informative:
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From Turquoise People discussion on Coin Silver: Coin Silver - #8 by TAH
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XRF Analyzer, Elemental Determination, Thermo Fisher Scientific | Thermo Fisher Scientific - US
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Niton XL5 Plus Handheld XRF Analyzer FAQs | Thermo Fisher Scientific - US
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XRF has also been used to determine real vs. fake turquoise. Article: Shining Like a Diamond…or Rhinestone: Identifying Precious Gems with XRF Analyzers | Blog Post | Olympus IMS and https://escholarship.org/content/qt9k84q2z8/qt9k84q2z8.pdf?t=rbtxz4
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https://www.nobelprize.org/prizes/physics/1901/speedread/. Discovery of X-rays. “On a dark November evening in 1895, Wilhelm Conrad Röntgen was perplexed by a fluorescent screen in his laboratory that was glowing for no apparent reason. Röntgen’s experiment on how cathode-ray tubes emit light appeared to be affecting something that was not part of the study. It took weeks spent eating and sleeping in his lab to identify the cause of this mysterious glow – a discovery with which Röntgen’s name is linked for all time, and which earned him the very first Nobel Prize in Physics in 1901.”
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XRF in combination with X-ray crystal structure X-ray crystallography - Wikipedia is one of the most accurate methods of determining mineral composition and structure, and even mining location (including turquoise). Note: X-ray crystallography is a very expensive technique and usually used in the art community by archeologists, museum curators, researchers, and collectors of high-value items from gems, minerals and paintings. Separately, these and other techniques are now frequently used in the art world to detect forgeries Macro X-ray fluorescence scanning (MA-XRF) as tool in the authentication of paintings - ScienceDirect and Investigating counterfeiting of an artwork by XRF, SEM-EDS, FTIR and synchrotron radiation induced MA-XRF at LNLS-BRAZIL - ScienceDirect .
For Turquoise, see for example: Non-invasive XRF analysis of ancient Egyptian and near Eastern turquoise: A pilot study - ScienceDirect
“Highlights
1400 ancient turquoises were studied using a combination of point and scanning XRF.
A correlation between chemistry and archaeological context was established.
Non-invasive XRF can help reconstruct the history of these ancient artifacts.”
- Note: The following is a little bit away from the history and science of turquoise and silver. However, many of you may find there is richness and insight in seeing the science, along with the beauty of the art, and the people who created it.
Richard Feynman: The Pleasure of Finding Things Out (BBC documentary program), https://topdocumentaryfilms.com/pleasure-finding-things-out/
Archimedes Palimpsest (Google Tech Talks) https://www.youtube.com/watch?v=Xe9uQVGkz9k
All the best!