Which minerals form along with diamonds at great depths and are brought to the surface by the same kimberlite or lamproite?

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

Answer: (C)

Diamonds form deep in the mantle under high pressure and are brought to the surface by kimberlite or lamprolite magmas. As these magmas ascend and crystallize, they carry along other mantle minerals that formed in the same deep environment. These minerals are called indicator minerals because their presence at the surface signals the likelihood of diamond-bearing rocks at depth. Common examples include garnet rich in pyrope, chromian diopside, chromite, and picroilmenite—minerals that crystallize under similar mantle conditions and survive transport to the surface. Prospectors use these indicators in heavy-mineral sampling to trace back to potential diamond-bearing pipes.

The other options don’t fit because they describe surface processes or concepts unrelated to mantle-derived minerals transported with diamonds. Marine deposits refer to sedimentary settings from seas, ore grade is about concentration and quality of ore, and drift refers to glacial movement.