What is the term for the concentration of diamonds in a deposit, measured by the amount of diamonds in 100 tons of earth removed?

• A. Drift
• B. Ore Grade
• C. Marine Deposit
• D. Indicator Minerals

Answer: (B)

Ore grade is the measure of how concentrated diamonds are in a deposit, usually expressed as carats per hundred tons of material. It directly tells you how rich a site is: more carats per 100 tons means more diamonds mined per unit of rock, which drives economic viability because processing less material yields more carats. In other words, the question is about how many diamonds you’d get from a specific amount of earth removed, which is exactly what ore grade quantifies. The other terms describe related ideas but not the concentration metric: a drift is a mine passage, a marine deposit refers to diamonds in marine environments, and indicator minerals are clues used to locate diamond-bearing rocks rather than quantify their concentration.