Results 71 to 80 of about 1,047 (213)

X-ray fingerprinting routine for cut diamonds

, 2022
S.40-57X-ray topography is a nondestructive technique that permits the visualization of internal defects in the crystal lattice of a gemstone, especially diamond, which is highly transparent to X-rays. This technique yields a unique "fingerprint" that is
Diehl, R., Herres, N.
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Educational actions in Gemology: extension-practices in public schools of Espírito Santo [PDF]

Introdução. No Brasil, a educação pública na rede básica de ensino enfrenta desafios relacionados ao acesso e à qualidade, o que demanda novas estratégias e metodologias capazes de promover um aprendizado significativo. O Projeto de Extensão Garimpando a
Depianti, Janaina Bastos, Magalhães, Marcus Vinicius Dutra de, Prata, Evelyn da Silva, Souza, Thallyta Nascimento Silva de   +3 more
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Characterizing Malysheva Emeralds (Urals, Russia) by Microscopy, Spectroscopy, Trace Element Chemistry, and Machine Learning

Crystals
The Malysheva emerald mine (Urals, Russia) boasts a long history and extraordinary emerald output. However, recent studies indicate that Malysheva emeralds share highly similar inclusion varieties, UV-visible-near infrared (UV-Vis-NIR) spectra, and ...
Yu-Yu Zheng, Xiao-Yan Yu, Bo Xu, Yu-Jie Gao   +3 more
doaj   +1 more source

Near-Infrared Spectroscopic Study of Biotite–Phlogopite (Mg# = 30~99): OH-Stretching Modes and Mg# Content Prediction Equation

Crystals
Biotite–phlogopite minerals are a complete Mg–Fe isomorphism series of phyllosilicates. A Fourier transform infrared spectroscopy (FTIR) and electron microprobe analysis (EMPA) were conducted on end-member phlogopite, Mg–biotite, and annite samples.
Zhentao Yang, Mingyue He, Shaokun Wu, Mei Yang, Bijie Peng   +4 more
doaj   +1 more source

Efeitos ópticos produzidos em gemas do grupo dos feldspatos

This article reviews the optical effects of feldspars, a group of minerals with various applications, including jewelry. Feldspars are divided into alkali and plagioclase, and exhibit effects such as adularescence, labradorescence and aventurescence ...
Godoy, Antônio Misson [UNESP], Bolonini, Thiago Motta   +1 more
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Comparative Study of Gemological and Spectroscopic Features and Coloration Mechanism of Three Types of Spodumene

Crystals
Spodumene is a characteristic mineral in lithium-rich granitic pegmatites, serving both as a valuable mineral resource and an important gem material. This study incorporates three different color varieties of spodumene—pink to violet, yellow-green, and ...
Zijia Zhou, Jing Liu, Kui He, Biao Yang, Yinghua Rao   +4 more
doaj   +1 more source

The analysis of natural gemstones and their synthetic counterparts using analytical spectroscopy methods [PDF]

Prompted by the increasing number, sophistication and quality of laboratory-grown gemstones; gemology has evolved into an individual science, incorporating the likes of biology and chemistry into its discipline.
Shah, Raabell
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Gemology, par Cornelius S. Hurlbut, Jr., et George S. Switzer, 1979

, 1980
Lagache Hubert. Gemology, par Cornelius S. Hurlbut, Jr., et George S. Switzer, 1979. In: Bulletin de Minéralogie, volume 103, 6, 1980.
Lagache, Hubert
core  

Gemological Abstracts [PDF]

Gems & Gemology, 1998
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Integrated Chromogenic Analysis of Freshwater Pearls: Revealing the Internal Factors Driving Color Variation

Crystals
Pearl color serves as the paramount criterion for quality assessment and commercial valuation in the global pearl industry. Freshwater nucleated pearls, which constitute 95% of global production, exhibit striking chromatic diversity. This study deciphers
Baoyi Yang, Bo Xu, Yi Zhao, Chenxi Zhang, Siyi Zhao, Zheyi Zhao   +5 more
doaj   +1 more source