scholarly journals Raman and Photoluminescence Mapping of Gem Materials

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 177
Author(s):  
Sally Eaton-Magaña ◽  
Christopher M. Breeding ◽  
Aaron C. Palke ◽  
Artitaya Homkrajae ◽  
Ziyin Sun ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
New Technology ◽  
Spatial Distributions ◽  
Raman Mapping ◽  
Heterogeneous Mixture ◽  
Spatial Differences ◽  
Pl Mapping ◽  
Origin Determination ◽  
Non Destructive ◽  
Calcium Carbonate Polymorphs

Raman and photoluminescence (PL) mapping is a non-destructive method which allows gemologists and scientists to evaluate the spatial distributions of defects within a gem; it can also provide a method to quickly distinguish different species within a composite gem. This article provides a summary of this relatively new technology and its instrumentation. Additionally, we provide a compilation of new data for various applications on several gemstones. Spatial differences within diamonds can be explored using PL mapping, such as radiation stains observed on the rough surface of natural green diamonds. Raman mapping has proven useful in distinguishing between omphacite and jadeite within a composite of these two minerals, identifying various tourmaline species within a heterogeneous mixture, and determining the calcium carbonate polymorphs in pearls. Additionally, it has potential to be useful for country-of-origin determination in blue sapphires and micro-inclusion analysis. As new avenues of research are explored, more applications for gem materials will inevitably be discovered.

CALCIUM CARBONATE POLYMORPHS IN FISH OTOLITHS: TOWARDS UNDERSTANDING ONTOGENETIC, ENVIRONMENTAL, AND PHYLOGENETIC CONTROLS

2018 ◽  
Author(s):  
Bryan C. Chakoumakos ◽  
◽  
Brenda M. Pracheil ◽  
R. Seth Wood ◽  
Alison Loeppky ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Fish Otoliths ◽  
Calcium Carbonate Polymorphs

NON-DESTRUCTIVE EXPERIMENTS AND MODELING OF CALCIUM CARBONATE FORMATION IN SOILS

2020 ◽  
Author(s):  
Carolyn D. Bland ◽  
◽  
Timothy M. Gallagher ◽  
Daniel O. Breecker
Keyword(s):  
Calcium Carbonate ◽  
Carbonate Formation ◽  
Non Destructive

Flotation behavior and mechanism of calcium carbonate polymorphs with sodium oleate as collector

2021 ◽  
pp. 117040
Author(s):  
Jingzhong Kuang ◽  
Xiaoyuan Wang ◽  
Mingming Yu ◽  
Weiquan Yuan ◽  
Zheyu Huang ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Sodium Oleate ◽  
Flotation Behavior ◽  
Calcium Carbonate Polymorphs

scholarly journals Luminescence reveals variations in local structural order of calcium carbonate polymorphs formed by different mechanisms

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Michael B. Toffolo ◽  
Giulia Ricci ◽  
Luisa Caneve ◽  
Ifat Kaplan-Ashiri
Keyword(s):  
Infrared Spectroscopy ◽  
Calcium Carbonate ◽  
Construction Materials ◽  
Reference Database ◽  
Formation Processes ◽  
X Ray Diffraction ◽  
Structural Order ◽  
Lime Plaster ◽  
Calcium Carbonate Polymorphs

Abstract In nature, calcium carbonate (CaCO3) in the form of calcite and aragonite nucleates through different pathways including geogenic and biogenic processes. It may also occur as pyrogenic lime plaster and laboratory-precipitated crystals. All of these formation processes are conducive to different degrees of local structural order in CaCO3 crystals, with the pyrogenic and precipitated forms being the least ordered. These variations affect the manner in which crystals interact with electromagnetic radiation, and thus formation processes may be tracked using methods such as X-ray diffraction and infrared spectroscopy. Here we show that defects in the crystal structure of CaCO3 may be detected by looking at the luminescence of crystals. Using cathodoluminescence by scanning electron microscopy (SEM-CL) and laser-induced fluorescence (LIF), it is possible to discern different polymorphs and their mechanism of formation. We were thus able to determine that pyrogenic calcite and aragonite exhibit blue luminescence due to the incorporation of distortions in the crystal lattice caused by heat and rapid precipitation, in agreement with infrared spectroscopy assessments of local structural order. These results provide the first detailed reference database of SEM-CL and LIF spectra of CaCO3 standards, and find application in the characterization of optical, archaeological and construction materials.

Non-Destructive Analysis of 14th–19th Century European Handmade Papers

2016 ◽  
Vol 37 (2) ◽  
Author(s):  
Timothy Barrett ◽  
Mark Ormsby ◽  
Joseph B. Lang
Keyword(s):  
Calcium Carbonate ◽  
19Th Century ◽  
Calcium Concentration ◽  
Natural Ageing ◽  
Destructive Analysis ◽  
Non Destructive ◽  
Over Time

AbstractNon-destructive analysis of 1,578 paper specimens made between the fourteenth and the nineteenth centuries was undertaken in an effort to better understand changes in paper composition over time and how these variations might affect paper stability during long term natural ageing. Gelatine content and colour were determined using UV/Vis/NIR spectrometry. Residual metals were measured using XRF. These components included potassium and sulfur as elements indicative of alum concentration; iron as a typical paper contaminant; and calcium, which is often associated with compounds such as calcium carbonate that can serve as alkaline reserves. The research demonstrated that papers that are lighter in colour (closer to white) are associated with higher levels of gelatine and calcium, and lower levels of iron. The survey also showed significant decreases in gelatine and calcium concentration over time with the largest differences coinciding with the rise of printing around 1500. The drop in pH over the centuries observed by other researchers is explained by the decreases in these two components rather than by a rise in alum concentration, which remained fairly stable. The craftsmanship of the specimens was evaluated using materials and workmanship ratings which showed better quality paper associated with higher gelatine and calcium concentrations and colour closer to white. Poorer quality papers were associated with higher iron levels and greater thickness.

scholarly journals The effect of different amino acids on spontaneous precipitation of calcium carbonate polymorphs

2018 ◽  
Vol 486 ◽  
pp. 71-81 ◽  
Author(s):  
Lara Štajner ◽  
Jasminka Kontrec ◽  
Branka Njegić Džakula ◽  
Nadica Maltar-Strmečki ◽  
Milivoj Plodinec ◽  
...  
Keyword(s):  
Amino Acids ◽  
Calcium Carbonate ◽  
Calcium Carbonate Polymorphs

X-Ray Diffraction Analysis of the Calcium Carbonate Polymorphs

1970 ◽  
Vol 14 ◽  
pp. 29-37 ◽  
Author(s):  
S. T. Silk ◽  
S. Z. Lewin
Keyword(s):  
Calcium Carbonate ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
Ray Method ◽  
X Ray ◽  
Packing Efficiency ◽  
Integrated Intensities ◽  
Packing Effect ◽  
Calcium Carbonate Polymorphs

AbstractIt is shown that the integrated intensities of diffraction lines from calcite and aragonite powders prepared by precipitation vary markedly, due to variations in sample packing efficiency arising from different degrees of polydispersity in the particle size distributions. Since prolonged grinding to equalize initially divergent distributions changes the polymorph composition, the packing effect imposes the principal limitation on the precision of the x-ray method for certain types of calcium carbonate preparations.

Characterization of Ni- and Ni(Pt)-Silicide Formation on Narrow Polycrystalline Si Lines by Raman Spectroscopy

1999 ◽  
Vol 591 ◽  
Author(s):  
P. S. Lee ◽  
D. Mangelinck ◽  
K. L. Pey ◽  
J. Ding ◽  
T. Osipowicz ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Raman Spectroscopy ◽  
Raman Mapping ◽  
Silicide Formation ◽  
Nucleation Sites ◽  
The Difference ◽  
The Stability ◽  
Non Destructive ◽  
Thermal Stability Of

ABSTRACTThe formation and thermal stability of Ni- and Ni(Pt) silicide on narrow polycrystalline Si (poly-Si) lines have been investigated using the non-destructive micro-Raman technique. The presence of Ni or Ni(Pt)Si on poly-Si lines with linewidths ranging from 0.5 gtm to 0.25 μm has been monitored by a distinct Raman peak at around 215 cm−1. Ni(Pt)Si was clearly identified to be present up to a RTA temperature of 900°C on narrow poly-Si lines as compared to pure NiSi which was found only up to 750°C. Raman scattering from the 100×100 μm2 poly-Si pads showed the formation of NiSi2 at 750°C for pure Ni-salicidation and 900°C for Ni(Pt)-salicidation respectively. The difference in the stability of NiSi on the poly-Si pads and lines is discussed in terms of agglomeration, inversion and/or nucleation of NiSi2that could be due to difference in nucleation sites and/or stress. In addition, a correlation between the line sheet resistance and the presence of Ni silicide was found using micro-Raman mapping along single poly-Si lines.

Sign in / Sign up

Export Citation Format

Share Document