Characteristics of Cordierite (Iolite) of Bandarguha-Orabahala Area, Kalahandi District, Odisha, IndiaDas SK* and Mohanty JK
Chief Scientist (Retd.), CSIR-IMMT, Odisha, India
- Corresponding Author:
- SK Das
Chief Scientist (Retd.)
CSIR-IMMT, Odisha, India
E-mail: [email protected]
Received Date: May 31, 2017; Accepted Date: June 23, 2017; Published Date: June 30, 2017
Citation: Das SK, Mohanty JK (2017) Characteristics of Cordierite (Iolite) of Bandarguha-Orabahala Area, Kalahandi District, Odisha, India. J Geol Geophys 6:294. doi: 10.4172/2381-8719.1000294
Copyright: © 2017 Das SK, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Optical microscopy, X-ray diffractometry, micro CT studies and mineral chemistry by SEM-EDS has been carried out on cordierite rich rock fragments from Bandarguha and Orabahala areas of Kalahandi district, Odisha. Macroscopically, cordierite grains exhibit distinct pleochroism in the shades of violet blue to light blue and colourless and are of gem quality (iolite). Biotite is the dominant associated mineral and Mg-Fe distribution coefficient (KD) between coexisting cordierite and biotite varies from 1.71 to 2.76. The cordierite is low cordierite (distortion index, Δ=0.257). Mineral analyses indicate that cordierite is magnesian rich (XMg=0.82-0.88) with limited Fe2+ substitution for Mg2+ and dichroism is due to presence of part of iron in ferric form. Cordierite is formed during metamorphism by reactions: (a) orthopyrox ene+sillimanite+quartz=cordierite+K-feldspar+water and (b) orthopyroxene+sillimanite=cordierite+corundum.