al·man·dine (?l?m?n-d?n?) also al·man·dite (-d?t?)n. A deep violet-red garnet, FeAl2Si3O12, found in metamorphic rocks and used as a gemstone.[Alteration of obsolete alabandyne, from Middle English alabandine, from Late Latin (gemma) alabandina, (gem) of Alabanda, from Alabanda, a town of ancient Asia Minor.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.al?man?dine (?æl m?n?din, -?da?n, -d?n) n. a purple-red iron aluminum garnet. [1670?80;