The growing popularity of laboratory-grown diamonds (LGDs) has sparked a widespread question among consumers: are these stones a genuine diamond or merely a sophisticated imitation? This confusion often stems from the fact that LGDs are produced in a factory setting, leading many to incorrectly assume they are a “fake” alternative. To resolve this, it is necessary to focus on the fundamental scientific definition of a diamond. The answer lies in the precise, measurable properties that define this unique crystal.
The Scientific Reality of Lab-Grown Diamonds
A diamond is scientifically defined as a material consisting essentially of pure carbon atoms crystallized in the isometric system. This specific atomic structure, where each carbon atom is bonded to four others, dictates the stone’s physical and chemical identity. The core makeup is what matters, regardless of whether it formed in the Earth’s mantle or in a controlled environment.
Lab-grown diamonds possess the exact same atomic lattice, making them chemically and structurally identical to their mined counterparts. They register the maximum hardness of 10 on the Mohs scale and exhibit the same density, light dispersion, and refractive index. Because LGDs replicate this fundamental crystalline structure, they are not diamond simulants, like cubic zirconia or moissanite, which have different chemical compositions. Scientifically speaking, a lab-grown diamond is a real diamond.
Manufacturing Processes
The creation of lab-grown diamonds relies on two primary technological methods, both of which introduce carbon to a pre-existing diamond seed crystal to foster growth.
High-Pressure/High-Temperature (HPHT)
The High-Pressure/High-Temperature (HPHT) technique mimics the extreme subterranean conditions where natural diamonds are formed. Diamond seeds are placed in a growth chamber alongside a carbon source, typically graphite, and a metallic solvent-catalyst.
This setup is subjected to immense pressures, exceeding 870,000 pounds per square inch, and temperatures ranging from 1300°C to 1600°C. The molten metal dissolves the carbon, allowing it to crystallize onto the seed as a rough diamond.
Chemical Vapor Deposition (CVD)
The second method is Chemical Vapor Deposition (CVD), which uses a vacuum chamber and lower temperatures, typically between 800°C and 1200°C. A thin slice of diamond seed is placed inside, and the chamber is filled with a carbon-rich gas, such as methane.
Microwave energy is used to break down the gas molecules, creating a plasma cloud of carbon atoms. These carbon atoms slowly settle and bond layer-by-layer onto the seed crystal, building a rough diamond over several weeks.
Distinguishing Features from Mined Diamonds
While LGDs are chemically identical to mined diamonds, the rapid, controlled nature of their growth leaves behind microscopic evidence used for identification. A primary distinction lies in the trace elements incorporated during formation. Most natural diamonds contain trace amounts of nitrogen, whereas many CVD-grown diamonds are nitrogen-free, and some HPHT stones may incorporate boron, which can impart a blue tint.
The internal growth patterns also differ due to the varied growth environments. Mined diamonds generally exhibit an octahedral growth pattern, reflecting their slow, multi-directional formation. HPHT diamonds often show a cuboctahedral structure, while CVD diamonds display a distinct layered structure caused by their one-directional growth process.
Gemologists use specialized equipment, such as fluorescence imaging and sophisticated spectroscopy, to detect these subtle structural and chemical identifiers. For instance, HPHT diamonds may contain tiny metallic inclusions from the growth process, and CVD diamonds can display unique strain patterns visible under polarized light.
Consumer Terminology and Market Labeling
To ensure transparency, regulatory bodies like the U.S. Federal Trade Commission (FTC) mandate clear disclosure for lab-grown diamonds at the point of sale. Sellers are required to use specific, approved terms that immediately convey the diamond’s origin to the consumer. The acceptable descriptors include “laboratory-grown,” “laboratory-created,” or “[manufacturer name]-created.”
The word “diamond” used without qualification implies a naturally mined stone. Therefore, LGDs cannot be marketed simply as “diamonds” or described with terms like “natural,” “genuine,” or “real” without the necessary preceding modifier. This legal framework ensures consumers are fully informed, acknowledging that while the stone is a chemically real diamond, its man-made origin must be clearly communicated.