Module Seven Quiz Back to Assignment Attempts Keep the Highest / 5 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 $2,000 per diamond, and the demand for diamonds is described by the following schedule: Price Quantity (Dollars) (Diamonds) ls 8,000 2,000 7,000 3,000 uccess Tips 6,000 4,000 5,000 5,000 access Tips 4,000 6,000 3,000 7,000 2,000 8,000 1,000 9,000