gemological

Etymology tree
English gem
Ancient Greek -ο- (-o-)der.
Latin -o-bor.
English -o-
Proto-Indo-European *leǵ-
Ancient Greek λόγος (lógos)
Proto-Indo-European *-h₂
Proto-Indo-European *-éh₂
Proto-Indo-European *-i-eh₂
Proto-Hellenic *-íā
Ancient Greek -ῐ́ᾱ (-ĭ́ā)
Ancient Greek -λογῐ́ᾱ (-logĭ́ā)bor.
Latin -logialbor.
French -logiebor.
English -logy
English -ology
English gemology
Proto-Indo-European *-ikos
Proto-Italic *-ikos
Latin -icuslbor.
Old French -iquebor.
Middle English -ic
Proto-Indo-European *h₂el-der.?
Proto-Italic *-ālis
Latin -ālisbor.
Old French -albor.
▲
Latin -ālis
Old French -elbor.
▲
Latin -ālisbor.
Middle English -al
Middle English -ical
English -ical
English gemological
From gemology + -ical.