corona

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photomicrograph of corroded garnet

corona

mineralogy

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metamorphic rock
Major features
…may be surrounded by a corona (reaction rim) of the mineral cordierite. Other minerals present in the matrix could include sillimanite, quartz, biotite, and alkali feldspar. These textural features suggest the following reaction relationship between garnet, sillimanite, quartz, and cordierite: garnet (2Mg₃Al₂Si₃O₁₂) + sillimanite (4Al
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…may be surrounded by a corona (reaction rim) of the mineral cordierite. Other minerals present in the matrix could include sillimanite, quartz, biotite, and alkali feldspar. These textural features suggest the following reaction relationship between garnet, sillimanite, quartz, and cordierite: garnet (2Mg₃Al₂Si₃O₁₂) + sillimanite (4Al
Read More