crystallized has 2 distinct synonyms spread across 2 of its 2 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is uncrystallized.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
having become fixed and definite in form
“distinguish between crystallized and uncrystallized opinion”
having both internal structure and external form of a crystal
“quartz crystal is perfectly crystallized”
Synonyms, antonyms and the broader and narrower relations for crystallized come from Princeton University’s WordNet. Full sources and licences.