'silica-rich' is a Modern English compound formed from 'silica' (from Neo‑Latin 'silica', ultimately from Latin 'silex/silicis' meaning 'flint, hard stone') and the adjective-forming element '-rich' (from Old English 'rice/ric' via Proto‑Germanic, now meaning 'having an abundance of').

'silica' developed from Latin 'silex/silicis' into New Latin 'silica' (meaning silicon dioxide) and was adopted into English as 'silica'; the element '-rich' descends from Old English 'rice/ric' (originally 'powerful/wealthy') and later became a productive suffix in Modern English; these elements were combined in scientific and descriptive usage in Modern English to form 'silica-rich'.

Originally, Latin 'silex' referred to 'flint' or 'hard stone' and Old English 'ric' implied 'power or wealth'; over time 'silica' came to denote the chemical silicon dioxide and '-rich' evolved into a productive suffix meaning 'abundant in', yielding the current sense 'containing a high proportion of silica'.