The phrase "irreplaceable resource" means something that cannot be easily substituted or replaced with something else because of its unique value or importance. Full definition
Indeed, cassava contributes more to the world's calorie budget than any other food except rice and wheat, which makes it a virtually irreplaceable resource against hunger. (scientificamerican.com)
If you decided to look for a health insurance online, check out irreplaceable resources byHealth Sherpa and NerdWallet. (personalmoneyservice.com)
Jacques Cousteau, conservationist (lived 1910 — 1997) «We must alert and organise the world's people to pressure world leaders to take specific steps to solve the two root causes of our environmental crises — exploding population growth and wasteful consumption of irreplaceable resources. (populationmatters.org)