What is a red or violet dyestuff having a greenish metallic luster. It is produced artificially, by the chemical dehydration of thionine, as a brown amorphous powder called?

thionol — A red or violet dyestuff having a greenish metallic luster. It is produced artificially, by the chemical dehydration of thionine, as a brown amorphous powder. (Webster's 1913.)

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