Which statement about identifying lab-grown diamonds is accurate?

• A. Lab-grown may show metallic inclusions or growth lines not typical of natural stones
• B. Natural stones always show metallic inclusions
• C. Lab-grown diamonds cannot be identified by growth features
• D. Natural stones show growth lines and color zoning exclusively

Answer: (A)

Understanding how a diamond formed helps you spot its origin. Lab-grown stones often carry growth features and inclusions tied to the production environment that natural stones don’t typically display. In HPHT-grown diamonds, metallic inclusions from the metal catalysts can become trapped inside the lattice, giving metallic-looking inclusions you wouldn’t usually see in natural diamonds. In CVD-grown stones, you often find clear growth lines or bands from the layer-by-layer deposition process, sometimes accompanied by distinct color zoning that reflects the growth sequence.

Natural diamonds form deep in the mantle and accumulate mineral inclusions that are ordinary minerals from the Earth, not metallic catalysts. Their internal features tend to be different in appearance and arrangement from those produced in a laboratory. So spotting metallic inclusions or growth lines that are not typical of natural stones is a practical way gemologists use to identify lab-grown diamonds.