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Showing posts from March, 2023

Gemstone Windows and Dark Patches: What to Look for in a Cut Gem

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AI-generated educational illustration. Conceptual only; not a photograph of an actual specimen or location. A coloured gem may have a pale, see-through centre or areas that look almost black. Both affect its appearance, but they do not have the same cause. What is a window? A window is an area where light passes through the gem instead of being returned towards the viewer. You may see the background through it, especially near the centre. Cutting angles and the material's refractive index—how it bends light—help determine whether this happens. There is no single ideal depth for every gemstone. Why dark patches need a closer look Darkness can have several causes. The material may absorb a lot of light. Some facets may reflect dark surroundings or the observer. Extinction is another cause, involving light that is not returned to the viewer after internal reflection. For that reason, calling every black patch “extinction” can be misleading. A simple viewing routine Look at the gem fac...
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Fourier-transform infrared spectroscopy / ftir working/ ftir testing / ftir analysis

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  Fourier-Transform Infrared Spectroscopy (FTIR) is an analytical technique used to identify and study the chemical properties of materials through their infrared spectrum. The FTIR technique is based on the concept of a Fourier transform – a mathematical operation used to convert a given function into its basic frequencies. FTIR uses a light source to provide radiation in the infrared spectral region. When this radiation is directed at a sample material, some of the radiation is absorbed by the sample material according to its chemical makeup. The radiation that is not absorbed passes through the sample and the absorptions are detected by a detector.   FTIR spectroscopy has a wide range of applications for physical and chemical characterization. The most common application is the identification of unknown substances through an analysis of the infrared spectrum produced. By comparing the infrared spectra of known substances, an unknown material can be identified. In additi...
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Understanding Raman spectra analysis / Raman Spectroscopy / Raman Shift

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 Raman spectroscopy  Raman Spectroscopy is a powerful analytical tool used to identify and characterize molecules. This technique is based on the fact that when photons interact with matter, some of them are scattered, with part of their energy being absorbed and emitted as Raman scattered radiation. This can include a range of photons from visible to infrared, making it possible to study a variety of materials of different characteristics, compositions, and physical states.   Raman scattering occurs when photons interact with molecular vibrations, causing shifts in the energy and the wavelength of the scattered photons. When this occurs, the wavelength length is shifted by an amount that is characteristic of the vibrational modes of the molecule, making it possible to identify specific molecules and structures. The amount of energy in the scattered radiation (the red shift or blue shift) relates to the intensity of the shift, and can be used to quantify the energy of...
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The Best Ways and advantages to Use EDXRF to Analyze Mineralogy

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  Energy Dispersive X-Ray Fluorescence (EDXRF) Energy Dispersive X-Ray Fluorescence (EDXRF) is a technique used to analyze the elemental composition of a material. It is a powerful analytical tool that is used by researchers from many different fields, from archaeology and art conservation to geology and environmental science.   EDXRF works by bombarding a sample with X-rays and then measuring the energy spectrum of X-rays that are produced by the sample. These X-rays are characteristic of each element present in the sample and by analyzing the X-rays, it is possible to deduce the chemical composition of the sample.   To begin the EDXRF analysis, the sample is placed in an X-ray generator. This X-ray generator consists of a X-ray tube, a collimator, and a detector. The X-ray tube is the source of X-rays that bombard the sample, while the collimator focuses the X-rays in one direction and reduces the noise in the measurements. The detector collects the X-rays that ...
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Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry (LA-ICP-MS)

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The most popular technique in gemstones & mineral testing. Advance Gemological Tools Laser ablation-inductively coupled plasma–mass spectrometry (LA–ICP–MS) is an analytical method used for trace element analysis. It combines a laser source for the ablation of small samples with an inductively coupled plasma source, which is an extremely hot gas source, to create ions from the sample. The ions then travel through an interface that separates the plasma from the mass spectrometer, which performs the mass spectrometric extraction of the ions according to their mass-to-charge ratio.  This technique was first developed in the early 1980s and has since become a ubiquitous tool for elemental and isotopic analysis. It offers a number of advantages over traditional analytical methods, such as high sensitivity, analytical speed, the ability to analyze very small samples, and multi-element analysis.   The LA–ICP–MS process begins with the laser ablation of a sample. A focused la...
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