Which statement about graphitization in diamonds is correct?

• A. Graphitization never occurs in HPHT treated diamonds
• B. Graphitization occurs only in natural, untreated diamonds
• C. Graphitization cannot happen in CVD diamonds
• D. Graphitization can also occur for HPHT treated diamonds

Answer: (D)

Graphitization means diamond converting to graphite, which happens when the crystal lattice is destabilized by heat and stress. This process isn’t limited to natural, untreated stones. Diamonds that have undergone HPHT treatment can still host areas where the lattice is susceptible to transformation, especially if they’re exposed to excessive heat or improper processing later on. That’s why this statement is correct: graphitization can occur in HPHT treated diamonds as well, not just in other types. The idea to keep in mind is that treatment doesn’t make diamonds immune to graphitization; it can introduce conditions that, under the right (or wrong) circumstances, allow the diamond to begin turning into graphite.