Which statement about diamond's thermal conductivity is correct?

• A. Diamond has higher thermal conductivity than most simulants.
• B. Diamond has lower thermal conductivity than most simulants.
• C. Diamond's thermal conductivity is the same as most simulants.
• D. Thermal conductivity is not used in diamond testing.

Answer: (A)

Thermal conductivity measures how quickly heat moves through a material. Diamond’s crystal structure, with incredibly strong covalent bonds and a highly ordered lattice, allows heat to travel through it very efficiently, giving it a high thermal conductivity. In practice, a thermal conductivity tester will read a high value for diamond, while common simulants such as cubic zirconia or glass conduct heat far more poorly and show much lower readings. Because diamond consistently shows higher thermal conductivity than most simulants, this property is a reliable way to distinguish diamond from many imitators during testing.