Diamonds, whether formed deep within the Earth or crafted in a laboratory, are both crystalline carbon. Lab-grown diamonds are not diamond simulants, but rather real diamonds created through processes that replicate the extreme conditions found in nature. To the unaided eye, these two types of diamonds appear visually identical due to their shared chemical composition and atomic structure. This makes distinguishing them complex for the general public.
Why Distinguishing Them Is Difficult
Lab-grown and natural diamonds are chemically, physically, and optically identical, making their differentiation profoundly challenging. Both are composed of pure carbon atoms arranged in the same crystal lattice structure, which gives them identical hardness, brilliance, and dispersion properties. They each rank a 10 on the Mohs hardness scale, signifying them as the hardest known substance. This means that in terms of durability, sparkle, and fire, a lab-grown diamond behaves exactly like a natural one. Their creation processes, whether natural geological formation over eons or controlled laboratory environments over weeks, yield the same molecular structure.
What the Naked Eye Cannot See
While lab-grown and natural diamonds can both contain inclusions, their specific types and patterns often differ. For instance, natural diamonds might exhibit mineral inclusions such as garnet or olivine, formed during their geological journey. In contrast, HPHT (High-Pressure High-Temperature) lab-grown diamonds may contain metallic inclusions from the growth catalyst, while CVD (Chemical Vapor Deposition) lab-grown diamonds can show distinctive growth striations or dark carbon inclusions. These distinguishing features are microscopic and require significant magnification, typically a 10x loupe or gemological microscope for a trained eye. Subtle differences in fluorescence or phosphorescence might also be present under specific UV light conditions. However, these variations are not reliable indicators for an untrained individual.
Expert Tools for Identification
Specialized scientific instruments are necessary to distinguish lab-grown from natural diamonds, as their differences often lie at the molecular or atomic level. UV/Visible spectroscopy reveals distinct absorption patterns related to nitrogen content or growth methods.
Infrared (FTIR) spectroscopy is used to determine the diamond type (e.g., Type Ia, Ib, IIa, IIb) based on the presence and aggregation state of nitrogen impurities, which can indicate origin. For example, most natural diamonds are Type Ia, containing nitrogen, while many lab-grown diamonds are Type IIa, with negligible nitrogen.
Raman spectroscopy combined with photoluminescence detects specific trace elements, defects, or growth-related features unique to lab-grown diamonds. This method can identify the presence of silicon-vacancy (SiV) centers in CVD diamonds or specific defects in HPHT diamonds that are uncommon in natural stones.
Advanced imaging instruments, such as DiamondView or DiamondSure, utilize short-wave UV light to reveal internal growth patterns and fluorescence reactions that are characteristic of either natural or laboratory formation. Interpreting the data from these sophisticated tools requires extensive gemological expertise and training.
The Importance of Certification
For consumers, the most reliable way to ascertain a diamond’s origin is through a reputable grading report from an independent gemological laboratory. Leading institutions like the Gemological Institute of America (GIA), International Gemological Institute (IGI), and Gem Certification & Assurance Lab (GCAL) explicitly identify lab-grown diamonds on their reports. These reports provide a comprehensive assessment of the diamond’s characteristics, including its origin.
Many lab-grown diamonds also feature a microscopic laser inscription on their girdle, indicating their laboratory origin. This inscription is not visible to the naked eye but can be seen under 10x magnification. Always purchasing diamonds with a valid, independent certification that clearly states the diamond’s origin ensures transparency and confidence in your purchase.