Indicator minerals help prospectors identify potential diamond-bearing regions because they originate from the same deep sources as diamonds.

Indicator minerals help prospectors identify potential diamond-bearing regions because they originate from the same deep sources as diamonds.

• A. False
• B. True
• C. Only found in marine deposits
• D. Only formed in shallow crust

Answer: (B)

Indicator minerals are signals of deep mantle sources, so their presence points to a geology capable of producing diamonds. Diamonds form at high pressures deep in the mantle, and the rocks that feed those diamonds carry minerals such as pyrope garnet, chromian spinel, chrome diopside, and ilmenite that crystallize only under those same conditions. Kimberlite magmas transport both diamonds and these minerals to the surface, so finding clusters of indicator minerals in surface rocks suggests a nearby diamond-bearing source. It’s not about surface rocks alone—the clue is the deep, mantle origin they share with diamonds. They aren’t restricted to marine deposits, nor are they tied to shallow crust formation.

Indicator minerals are signals of deep mantle sources, so their presence points to a geology capable of producing diamonds. Diamonds form at high pressures deep in the mantle, and the rocks that feed those diamonds carry minerals such as pyrope garnet, chromian spinel, chrome diopside, and ilmenite that crystallize only under those same conditions. Kimberlite magmas transport both diamonds and these minerals to the surface, so finding clusters of indicator minerals in surface rocks suggests a nearby diamond-bearing source. It’s not about surface rocks alone—the clue is the deep, mantle origin they share with diamonds. They aren’t restricted to marine deposits, nor are they tied to shallow crust formation.