Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and Geochronology

The trapiche garnet, a gemstone of unparalleled beauty, boasts a rare structure comprising one core, six radiating arms, and a main body. The occurrence of garnet within the trapiche structure elevates it beyond the species, granting it significant scientific and gemological value. In this study, we...

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Main Authors: Yingzhao Wang, Siyi Zhao, Yi Zhao, Zisheng Wang
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/3/201
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author Yingzhao Wang
Siyi Zhao
Yi Zhao
Zisheng Wang
author_facet Yingzhao Wang
Siyi Zhao
Yi Zhao
Zisheng Wang
author_sort Yingzhao Wang
collection DOAJ
description The trapiche garnet, a gemstone of unparalleled beauty, boasts a rare structure comprising one core, six radiating arms, and a main body. The occurrence of garnet within the trapiche structure elevates it beyond the species, granting it significant scientific and gemological value. In this study, we conducted the first systematic investigation of trapiche garnets from the Chun’an area, Zhejiang Province, China. These samples were proven grossular through the analysis of spectroscopy and major elements. The trace element features are consistent with the distribution patterns of garnet in hydrothermal metasomatic skarn. Microscopic observation and Raman spectroscopy revealed that dark inclusions within the core and arms consist predominantly of amorphous carbon. The in situ U-Pb dating of the trapiche garnets revealed a crystallization age of 120.7 ± 4.7 Ma, corresponding to the late Yanshanian movement. It is speculated that the contact metasomatism between magma enriched in Al and surrounding rock led to the formation of calcareous skarn. This study provides insights into gemological, geochemical, and chronological characteristics, broadening the research on trapiche structures, and enhancing the understanding of gemstone mineralization timing and local tectonic activity.
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series Crystals
spelling doaj-art-7f96a3c6fde64dd1a7d3cd04f89ed2bc2025-08-20T02:42:46ZengMDPI AGCrystals2073-43522025-02-0115320110.3390/cryst15030201Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and GeochronologyYingzhao Wang0Siyi Zhao1Yi Zhao2Zisheng Wang3Shandong Institute of Geological Survey, Jinan 250014, ChinaSchool of Gemmology, China University of Geosciences, Beijing 100083, ChinaSchool of Gemmology, China University of Geosciences, Beijing 100083, ChinaNo.1 Institute of Geology and Mineral Resource Exploration of Shandong Province, Jinan 250100, ChinaThe trapiche garnet, a gemstone of unparalleled beauty, boasts a rare structure comprising one core, six radiating arms, and a main body. The occurrence of garnet within the trapiche structure elevates it beyond the species, granting it significant scientific and gemological value. In this study, we conducted the first systematic investigation of trapiche garnets from the Chun’an area, Zhejiang Province, China. These samples were proven grossular through the analysis of spectroscopy and major elements. The trace element features are consistent with the distribution patterns of garnet in hydrothermal metasomatic skarn. Microscopic observation and Raman spectroscopy revealed that dark inclusions within the core and arms consist predominantly of amorphous carbon. The in situ U-Pb dating of the trapiche garnets revealed a crystallization age of 120.7 ± 4.7 Ma, corresponding to the late Yanshanian movement. It is speculated that the contact metasomatism between magma enriched in Al and surrounding rock led to the formation of calcareous skarn. This study provides insights into gemological, geochemical, and chronological characteristics, broadening the research on trapiche structures, and enhancing the understanding of gemstone mineralization timing and local tectonic activity.https://www.mdpi.com/2073-4352/15/3/201garnettrapichechemical compositionsU–Pb dating
spellingShingle Yingzhao Wang
Siyi Zhao
Yi Zhao
Zisheng Wang
Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and Geochronology
Crystals
garnet
trapiche
chemical compositions
U–Pb dating
title Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and Geochronology
title_full Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and Geochronology
title_fullStr Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and Geochronology
title_full_unstemmed Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and Geochronology
title_short Trapiche Garnets in Chun’an, Zhejiang Province, China: New Constraints from Their Gemology, Geochemistry, and Geochronology
title_sort trapiche garnets in chun an zhejiang province china new constraints from their gemology geochemistry and geochronology
topic garnet
trapiche
chemical compositions
U–Pb dating
url https://www.mdpi.com/2073-4352/15/3/201
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AT siyizhao trapichegarnetsinchunanzhejiangprovincechinanewconstraintsfromtheirgemologygeochemistryandgeochronology
AT yizhao trapichegarnetsinchunanzhejiangprovincechinanewconstraintsfromtheirgemologygeochemistryandgeochronology
AT zishengwang trapichegarnetsinchunanzhejiangprovincechinanewconstraintsfromtheirgemologygeochemistryandgeochronology