symbol vs symbolical

symbol is a noun but symbolical is not a noun.

Word	Noun	Adjective	Verb	Adverb
symbol	Yes	No	No	No
symbolical	No	Yes	No	No

symbol (noun)	symbolical (noun)
something visible that by association or convention represents something else that is invisible
an arbitrary sign (written or printed) that has acquired a conventional significance

symbol (adjective)	symbolical (adjective)
	relating to or using or proceeding by means of symbols
	serving as a visible symbol for something abstract