'hornblende-rich' is a compound formed from 'hornblende' (originally from German 'Hornblende', where 'Horn-' meant 'horn' and 'Blende' meant 'deceiver' or 'that which blinds/varnishes') and the English element '-rich' (from Old English 'rice'/'ric', meaning 'having abundance of').

'hornblende' was borrowed into English from German 'Hornblende' (18th century) to name the dark amphibole mineral; the adjective form 'hornblende-rich' arose in geological English by combining that mineral name with the productive English suffix '-rich' to describe rocks abundant in the mineral.

Originally the term referred to the mineral name ('hornblende'); over time the compound 'hornblende-rich' came to be used adjectivally to mean 'having a high proportion of hornblende' in a rock or material.