Which type of diamonds are crustal diamonds associated with crustal formation and industrial use?

• A. Crustal diamonds
• B. Mantle diamonds
• C. Carbonado
• D. Blue diamonds

Answer: (A)

Crustal diamonds are formed in the Earth's crust under relatively lower pressures than diamonds that crystallize deep in the mantle. Because they originate in crustal rocks and can appear as polycrystalline or microcrystalline forms, they are the type most commonly linked with industrial use, where diamond’s hardness and abrasive properties are valuable. Mantle diamonds form deeper in the mantle under higher pressures and are not defined by an association with industrial applications. Blue diamonds are a color variety caused by boron and aren’t defined by where they form, and carbonado is a separate, often crustally sourced, polycrystalline form with debated origin. So the term that directly aligns with crustal formation and typical industrial use is crustal diamonds.