Most Type I diamonds are a mix of more than one diamond type.

• A. True.
• B. False.
• C. Most Type I diamonds are a mix of more than one diamond type.
• D. Not enough data.

Answer: (C)

In diamond type classification, Type I means nitrogen is present and its arrangement matters. Within Type I, nitrogen can occur as isolated atoms (Type Ib) or in aggregated clusters (Type Ia), and many Type I diamonds actually show both forms or a mix of aggregation states in different parts of the crystal. So, while the diamond remains Type I overall, the nitrogen environment isn’t uniform—you can have a mixture of nitrogen configurations within the same crystal. That’s why the statement describing Type I diamonds as a mix of more than one diamond type is the best way to express the idea: you’re seeing different nitrogen configurations within Type I, not a mixture of Type I with Type II. The other options don’t fit because Type I isn’t defined by mixing two major diamond types, and there is enough data to recognize the presence of multiple nitrogen configurations within Type I.