Natural diamonds form deep within the Earth’s mantle over billions of years under intense heat and pressure. Lab-grown diamonds are cultivated in controlled laboratory environments, replicating these conditions over weeks or months. Both share an identical chemical composition of pure carbon and the same crystal structure. This fundamental similarity raises questions about whether standard diamond testing equipment can differentiate between them.
Understanding Standard Diamond Testers
Standard diamond testers measure thermal or electrical conductivity, properties inherent to diamond. Thermal testers, the most common type, work because diamonds are exceptional thermal conductors. These devices measure how quickly heat dissipates from a heated tip touching the stone. Diamonds conduct heat far more efficiently than most diamond simulants, like cubic zirconia or moissanite. The tester’s sensor detects this rapid heat transfer, indicating a diamond. Some testers also consider electrical conductivity; diamonds are electrical insulators. These testers identify a stone as diamond based on these physical properties, distinguishing it from non-diamond materials, not discerning its origin.
How Lab-Grown Diamonds React to Standard Testers
Lab-grown diamonds consistently pass standard diamond testers because they are, fundamentally, diamonds. They share the identical chemical composition and crystal structure of natural diamonds, exhibiting the same thermal and electrical conductivity. When tested, heat dissipates from a lab-grown diamond at the same rapid rate as a natural one, resulting in a “pass.” They also behave identically as electrical insulators. This identical reaction occurs because lab-grown diamonds are actual diamonds, not simulants like cubic zirconia or moissanite. Their laboratory creation replicates natural conditions, producing a product physically and chemically indistinguishable by these basic testing methods.
Methods for Distinguishing Lab-Grown from Natural Diamonds
Since standard testers cannot differentiate diamond origin, specialized gemological equipment and techniques are employed. One method involves observing their reactions to ultraviolet (UV) light. Many natural diamonds display varying degrees of blue fluorescence under longwave UV light, and some may show phosphorescence. Some lab-grown diamonds, particularly those grown by the High-Pressure/High-Temperature (HPHT) method, can exhibit different fluorescence colors, patterns, or distinct phosphorescence.
Spectroscopy is another sophisticated technique used for identification. This involves analyzing how light interacts with the diamond at different wavelengths. Natural diamonds often contain trace amounts of nitrogen, which can produce specific absorption patterns detectable through infrared or UV-Vis-NIR spectroscopy. Lab-grown diamonds, especially those produced by Chemical Vapor Deposition (CVD), typically lack these nitrogen impurities or show different spectral signatures related to their growth process or specific impurities like boron.
Under high magnification, gemologists can also examine internal growth patterns. Natural diamonds typically exhibit octahedral growth patterns. Lab-grown diamonds, however, can display distinctive growth structures such as cubic or cuboctahedral patterns, or striations, which are indicative of their controlled growth environment. These subtle features are often invisible to the naked eye but become apparent with advanced microscopic analysis. Specialized screening devices are also available that combine these principles, using advanced optics and software to quickly identify potential lab-grown diamonds, requiring further examination by a gemological laboratory.
Significance for Consumers and the Market
Accurately distinguishing between natural and lab-grown diamonds is important for consumers and the market. Disclosure is paramount: jewelers must clearly state a diamond’s origin. This transparency ensures informed purchasing decisions and prevents consumers from mistakenly buying one type for the other.
Differences exist in market value and pricing. Natural diamonds are a finite resource, contributing to their traditional rarity and pricing. Lab-grown diamonds, produced in a controlled environment, generally have a different supply dynamic and are often more accessibly priced. This affects investment and resale value.
Maintaining consumer confidence relies on accurate identification and clear labeling. Reputable gemological laboratories like GIA, IGI, and GCAL certify both natural and lab-grown diamonds. These certifications provide independent verification of a diamond’s characteristics and origin, ensuring authenticity and proper disclosure.