Journal of the Mineralogical Society of Korea (한국광물학회지)

The Mineralogical Society of Korea (한국광물학회)
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Application of FTIR on the Study of Spectroscopic Characteristics on Emerald from Itabira, Brazile

FTIR을 이용한 브라질 Itabira 지역 에메랄드의 분광학적 특성 연구

  • Lim, Ye-Won (Department of Geology, Kyungpook National University) ;
  • Jang, Yun-Deuk (Department of Geology, Kyungpook National University) ;
  • Kim, Jong-Rang (Department of Geology, Kyungpook National University) ;
  • Kim, Hyeong-Soo (Department of Earth Sciences Education, Kyungpook National University) ;
  • Kim, Jong-Gun (Department of Gemology, Daegu Polytechnic College) ;
  • Kim, Jeong-Jin (Department of Earth and Environmental Sciences, Andong National University)
  • 임예원 (경북대학교 자연과학대학 지질학과) ;
  • 장윤득 (경북대학교 자연과학대학 지질학과) ;
  • 김종랑 (경북대학교 자연과학대학 지질학과) ;
  • 김형수 (경북대학교 사범대학 지구과학교육과) ;
  • 김종근 (대구산업정보대학 보석감정학과) ;
  • 김정진 (안동대학교 지구환경과학과)
  • Published : 2008.12.30
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Abstract

Emerald deposit located on Itabira, Brazil is one of the major one in the world. We applied three different analytical approaches on Itabira emerald samples, (1) perpendicular to the c-axis, (2) parallel to the c-axis, (3) emerald pallet mixed with KBr, using Fourier Transform Infrared (FTIR) spectroscopy, to understand and compare spectroscopic characteristics of three Itabira emerald samples. Occurrence of $5,271\;cm^{-l}$ and $1,638\;cm^{-l}$ absorption peaks within $H_2O$-related range indicates that the samples belong to Type-II emerald. These emerald samples also display strong absorption peak generated from Type-IIa emerald preserving $H_2O-Na-H_2O$ sequence. $CO_2$- and Cl-related absorption peaks observed within specific range except for $H_2O$-related range. These observations and results suggest that FTIR analysis can be used for not on1y classification of emerald types, but also prediction of $Na_2O$ content within the emerald through comparison of relative peak intensity.

현재 에메랄드의 중요한 산지로 자리 잡아가고 있는 Itabira 지역 에메랄드의 분광학적 특성을 연구하기 위하여 에메랄드를 C-축에 수직, 수평인 방향으로 각각 절단하였으며, $H_2O$ 관련 범위의 좀더 세부적인 피크 관찰을 위하여 KBr로 압축한 pellet시료를 만들어 적외선 분광분석(FTIR) 실험을 수행하였다. $H_2O$ 관련 범위에서 $5,271\;cm^{-1}$, $1,638\;cm^{-1}$ 피크가 나타나는 것으로 보아 본 시료는 Type-II에 해당함을 관찰할 수 있었으며, $H_2O-Na-H_2O$ 배열 형태를 가지는 Type-IIa에 해당하는 피크가 아주 강하게 나타나고 있다. $H_2O$ 관련 범위를 제외한 특정 범위에서는 $CO_2$, Cl 피크 등이 관찰되었으며, 적외선 분광분석 법을 이용하여 타입의 분류뿐만 아니라 상대적인 피크 강도 비교를 통하여 $Na_2O$ 함량 또한 예측 가능한 것으로 사료된다.

Keywords

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