Lab-created diamonds and natural diamonds are chemically, physically, and optically the same material, composed of pure carbon atoms arranged in the same crystal structure. Their distinct origins, however, lead to subtle differences that affect identification and market value. The fundamental difference lies in their formation process: one is a product of geological forces over billions of years, while the other is grown in a laboratory in a matter of weeks. Sophisticated methods are used to accurately determine a diamond’s origin for consumer transparency and valuation.
Creation Methods and Origin
Natural diamonds form deep within the Earth’s mantle, typically at depths of 150 to 250 kilometers, under immense pressure and temperatures between 900 and 1,300 degrees Celsius. These conditions cause carbon to crystallize into the stable diamond structure over billions of years. They are brought to the surface through rare, deep-source volcanic eruptions that form kimberlite and lamproite pipes.
Lab-created diamonds are grown in controlled environments using one of two primary industrial techniques. The High-Pressure/High-Temperature (HPHT) method mimics the Earth’s conditions by placing a carbon source and a tiny diamond seed into a press. Subjected to pressures of around 5.5 gigapascals and temperatures between 1,300 and 1,600 degrees Celsius, the carbon dissolves in a molten metal flux and crystallizes onto the seed over days or weeks.
The second method, Chemical Vapor Deposition (CVD), uses lower pressures and temperatures. A diamond seed is placed in a vacuum chamber filled with carbon-containing gases, such as methane and hydrogen. Microwaves break down these gases into a plasma cloud, allowing carbon atoms to crystallize layer-by-layer onto the seed over several weeks. This process often results in diamonds that require post-growth HPHT treatment to improve their color.
Scientific Structure and Composition
Both natural and lab-grown diamonds share the same cubic crystal lattice, giving them their hardness and brilliance. However, the different growth environments introduce variations in trace elements and crystal growth patterns. Natural diamonds form slowly and often incorporate trace amounts of nitrogen, leading to the common Type Ia classification, which accounts for up to 98% of all mined diamonds.
The rapid, controlled growth of lab diamonds leads to distinct structural characteristics that scientists can measure. HPHT diamonds are grown using a metal solvent (nickel, iron, or cobalt), and trace amounts of these metals can become trapped, resulting in metallic inclusions. CVD diamonds are grown in layers, which can result in the incorporation of elements like silicon or boron, creating a distinctive layered structure visible under high magnification.
Natural diamonds generally grow in an octahedral shape, resulting in complex, multi-directional growth zones. In contrast, the rapid, controlled growth of lab diamonds results in simpler, more uniform patterns. HPHT growth commonly shows a cuboctahedral pattern, while CVD growth exhibits a characteristic columnar or layered structure. These microscopic differences are the diamond’s “fingerprint” of origin.
Professional Identification Techniques
Since lab-created diamonds are chemically identical to natural diamonds, standard tools like thermal testers cannot distinguish them. Specialized equipment is required, with advanced spectroscopy being one of the most effective non-destructive identification methods. Fourier-Transform Infrared (FTIR) spectroscopy detects trace elements like nitrogen; most natural diamonds show distinct absorption peaks, while lab-grown diamonds often lack these nitrogen-related features.
Ultraviolet-Visible (UV-Vis) spectroscopy detects specific absorption centers unique to each origin, such as the N3 center in natural diamonds. The DiamondView instrument uses short-wave UV light to observe the diamond’s fluorescence and phosphorescence patterns. While natural diamonds often show blue fluorescence under long-wave UV, lab-grown diamonds often exhibit stronger, characteristic colors like orange, yellow, or teal under short-wave UV.
The DiamondView also reveals the internal growth structure, which is a definitive indicator of origin. HPHT diamonds display characteristic cubic or cruciform growth sectors, while CVD diamonds show clear parallel striations or layered growth patterns. Gemologists also look for specific inclusions: HPHT stones may be magnetic due to metallic flux inclusions, and CVD stones can contain non-diamond carbon or silicon-vacancy defects. These inclusions contrast with the mineral crystals typically found in natural diamonds.
Market Value and Pricing
The primary difference for consumers is the price, driven by the economics of supply. Lab-created diamonds typically cost 30% to 70% less than natural diamonds of comparable size and quality due to scalable production methods. As manufacturing processes become more efficient, the price of lab-grown diamonds continues a downward trend, mirroring the market for technological goods.
Natural diamonds retain a higher residual value because they are a finite resource requiring extensive mining operations. However, lab-created diamonds currently hold virtually no resale value in the secondary market, often selling for less than 10% to 30% of their original retail price. The industry is mandated to clearly label lab-grown diamonds as “synthetic,” “man-made,” or “lab-grown” to ensure transparency.