Here's what rhymes with greenstone.

Consider these alternatives

gneiss / price orogenic / academic granites / rights obsidian / meridian lazuli / newly metavolcanic / organic pyrite / highlight sedimentary / century metasedimentary / century terrane / main diabase / case plutonic / chronic flysch / this rhyolite / right quarried / storied gneisses / prices cassiterite / feet carnelian / epithelium steatite / might