Precious and Decorative Stones

2023: No. 1 (111) CONTENTS

DOI: https://doi.org/10.53036/2023-1(111)-3

GEMOLOGICAL RESEARCH OF THE SPINEL WITH ASTERISM AND COLOR CHANGE EFFECT

Yu. Gayevsky
State Gemmological Centre of Ukraine

О. Belichenkо
State Gemmological Centre of Ukraine

N. Vovk
Internet shop: nvovkjewerly.com.ua

Language: Ukrainian

Precious and Decorative Stones. No. 1 (111), 2023: 20–22

Abstract
The results of the natural opaque pink-purple spinel gemological study are given. Gemological characteristics were determined, microscopic examination, quantitative X-ray fluorescence analysis (EXDRF) and IR-Fourier spectroscopy were carried out. It was defined that the spinel has rare optical effect – a double asterism. Six-pointed star is visible on the surface of the cabochon top and four-pointed star is on the side surface. The sample is characterized by the color change effect as well, from purple-blue under the daylight gemological lamp to orange-red under the incandescent light. Such natural spinels are extremely rare not only on the Ukrainian, but also on the world jewelry market.

Keywords: spinel, asterism, color change effect, gemological research, microscopy, X-ray fluorescence analysis.

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