Which feature is typically mined for primary diamond deposits?

Which feature is typically mined for primary diamond deposits?

• A. Alluvial deposits
• B. Deep mantle sources
• C. Marine placers
• D. Kimberlite pipes

Answer: (D)

When identifying primary diamond deposits, look for the rock that carries diamonds from deep in the mantle to near the surface. Diamonds reach the surface most commonly inside kimberlite pipes, which are tubular volcanic formations that crystallize from kimberlite magma and can trap diamonds in their host rock. This makes kimberlite pipes the main mining targets for primary deposits, since the diamonds are still intergrown with the rock they formed in. Alluvial deposits and marine placers represent secondary deposits—diamonds weathered from the original rock and transported and concentrated by water—so they are not primary sources. The idea of a deep mantle source refers to where diamonds originate, not a mined feature; the mining focus is on the surface expression of that source, i.e., the kimberlite pipes.

When identifying primary diamond deposits, look for the rock that carries diamonds from deep in the mantle to near the surface. Diamonds reach the surface most commonly inside kimberlite pipes, which are tubular volcanic formations that crystallize from kimberlite magma and can trap diamonds in their host rock. This makes kimberlite pipes the main mining targets for primary deposits, since the diamonds are still intergrown with the rock they formed in. Alluvial deposits and marine placers represent secondary deposits—diamonds weathered from the original rock and transported and concentrated by water—so they are not primary sources. The idea of a deep mantle source refers to where diamonds originate, not a mined feature; the mining focus is on the surface expression of that source, i.e., the kimberlite pipes.