Colour of Precious Opal

  title={Colour of Precious Opal},
  author={John V. Sanders},
Genèse de silice supergène sur Terre et implications sur Mars
La silice (SiO2), composant important des planetes telluriques, se trouve sous diverses formes. La genese de ses polymorphes amorphes et mal cristallises (opale-A, opale-CT, calcedoine) est encore
Paleomagnetic dating of ironstone nodules (‘nuts’) from the Yowah opal field, central southern Queensland
ABSTRACT To constrain the age of Australian opal formation, we have undertaken a paleomagnetic study of oxidised ironstone ‘nuts’ from Yowah, Queensland. Following standard methods, we have
Dental composites for wide color matching
Nanotechnology-based dental composites, see Tokuyama Dental's OMNICHROMA, can address the issue of color mismatch between tooth and filling. Similar to a chameleon, the filling can match the color of
Formation of Sediment-Hosted Opal-AG at Lightning Ridge (New South Wales, Australia): Refining the Deep Weathering Model
Formation of sedimentary opal-AG in opal fields of eastern Australia has been linked to intensive weathering of their Cretaceous host rocks—the “deep weathering” model. Here we examine possible links
Self-Assemblies of Gold Nanocrystals: Unexpected Properties
  • M. Pileni
  • Chemistry
    The Journal of Physical Chemistry C
  • 2021
An Experimental and Theoretical Determination of Oscillatory Shear-Induced Crystallization Processes in Viscoelastic Photonic Crystal Media
A complementary generic spatio-temporal model is developed of crystallization due to shear-dependent interlayer viscosity, giving propagating crystalline fronts with increasing applied strain, and a gradual transition from interparticle disorder to order.
Understanding hierarchical spheres-in-grating assembly for bio-inspired colouration
Mechanistic and predictive understanding is provided on spheres-in-grating assembly towards hierarchical structure with colouration effects as found in nature, exploiting embossed polymer gratings
Anisotropic Iridescence and Polarization Patterns in a Direct Ink Written Chiral Photonic Polymer
This work synthesizes a suitable chiral nematic liquid crystal elastomer ink is synthesized for direct ink writing, which self-assembles into a chiral photonic structure, which exhibits atypical iridescence and polarization selectivity.
Silicon-Oxygen Region Infrared and Raman Analysis of Opals: The Effect of Sample Preparation and Measurement Type
An extensive infrared (IR) spectroscopy study using transmission, specular and diffuse reflectance, and attenuated total reflection (ATR) was undertaken to characterise opal-AG, opal-AN (hyalite),


The opal book
Die Optik der Edelopale
Inhalt . Einleitung 183 1. Die homogenen Louchtkömer 184 2. Methodisches 185 3. Beschreibung der Erscheinung 187 4. Die verschiedenen Reflektogrammtypen 189 ö. Großzwillinge 196 6. Allgemeines zur
Über Bragg‐Reflexe mit sichtbarem Licht an monodispersen Kunststofflatices. I
Mit Hilfe von Durchsicht- und Reflexionsspektren werden die Farberscheinungen an monodispersen Latices als Bragg-Reflexe mit sichtbarem Licht identifiziert. Durch eine vollstandige Strukturanalyse
The structure of opal and the origin of its iridescence
SummaryA study of the optical behaviour of iridescent opal indicates very clearly that the silica present in the material has a regularly stratified structure in which the alternate layers differ in
Structure of Opal
SINCE the work of Flörke1 it has generally been accepted that natural opaline silicas fall into two broad categories: (1) specimens which give X-ray patterns indicative of an obviously, although in