Precious and Decorative Stones

2024: No. 3-4 (117-118) CONTENTS

DOI: https://doi.org/10.53036/2024-3-4(117-118)-1

Comparison of decorative and gemological characteristics of snow obsidian from American and Ukrainian deposits

V. Surova
State Gemmological Centre of Ukraine

O. Horobchyshyn
State Gemmological Centre of Ukraine

Language: Ukrainian

Precious and Decorative Stones. No.3-4 (117-118), 2024: 4–8

Abstract
The article explores the gemological and decorative characteristics of snowflake obsidian from deposits in Ukraine, the USA, and Mexico.
The introduction is dedicated to the history of obsidian usage, as well as descriptions of its varieties, global distribution, and major geological obsidian provinces. A study and comparison of the physical-chemical properties and gemological characteristics of obsidian from different regions were conducted using standard gemological methods. It was found that Ukrainian snowflake obsidian predominantly exhibits gray and light gray colors, while the American variety is mainly black. Differences in texture patterns were also noted: Ukrainian obsidian is characterized by fine-spherulitic, spherulitic-inclusion, and spherulitic-striped patterns, while the American variety has a coarse-spherulitic pattern. Ukrainian obsidian has higher density and refractive index compared to the American counterpart. The defects of obsidian were also considered separately.
The study highlights the potential of Ukrainian obsidian as a valuable material for jewelry and carving works; however, its sporadic occurrence is a major limitation for its utilization. The described results can be useful for further research into the gemological and mineralogical properties of obsidian, as well as its applications in various industries.

Keywords: obsidian, snowflake obsidian, gemological characteristics, decorative properties.

References

Ancient Egyptian Mirror | Arte egipcio, Arte antiguo, Egipto. [Photo]. (n. d.). Pinterest. https://www.pinterest.com/pin/475552041884256138/

Discussions. (2022, August 24). Mindat.org. https://www.mindat.org/mesg-602692.htm

Elwell, D. (1986). Artificial precious stones. Mir [in Russian].

Gorbachevskaya, O. (1953). Report of the Transcarpathian thematic party on the results of geological research conducted in 1952 in the area of the central part of the Velikiy Sholes ridge. Transcarpathian thematic party [in Russian].

Mitrokhin, O. (2024). Field guide to rocks. Publishing and Printing Center "Kyiv University" [in Ukrainian].