4. Oligopolies and Cartels A large share of the world supply of diamonds comes from Russia and South Africa. Suppose that the marginal cost of mining diamonds is constant at $1,000 per diamond, and the demand for diamonds is described by the following schedule: Price Quantity (Dollars (Diamonds ) ) 8,000 5,000 7,000 6,000 6,000 7,000 5,000 8,000 4,000 9,000 3,000 10,000 2,000 11,000 1,000 12,000 If there were many suppliers of diamonds, the price would be $1,000 per diamond and the quantity sold would be 12,000 diamonds. Points: 1/ 1 Close Explanation Explanation: The equilibrium price and quantity in a competitive market are determined by the intersection of the demand and marginal-cost curves. In this case, marginal cost is constant at $1,000 per diamond, so the equilibrium price would be $1,000 per diamond and 12,000 diamonds would be sold. If there were only one supplier of diamonds, the price would be $7.000 per diamond and the quantity sold would be a non