a gold mine of information

Origin

Before the digital age, true wealth was often found buried deep within the earth. Prospectors, enduring harsh conditions, toiled tirelessly, driven by the dream of striking a 'gold mine'—a rich vein promising immense riches. This arduous quest for precious metal naturally gave rise to the phrase, which, by the 20th century, had brilliantly broadened its scope. It leapt from the gritty reality of geology to describe any immensely valuable source, particularly when referring to the non-physical, yet equally coveted, bounty of knowledge and facts. Thus, a vast library or an experienced expert became a 'gold mine of information,' mirroring the exhaustive, rewarding effort required to unearth their hidden treasures.