Editor’s Note
The Gemological Institute of America (GIA) has announced a significant shift in its grading approach for lab-grown diamonds, moving away from the traditional 4Cs system to a new descriptive rating scale. This change, effective late 2025, marks a pivotal step in distinguishing the evaluation of synthetic stones from their natural counterparts.
The Gemological Institute of America (GIA), the authoritative body in gemstone identification, announced a major reform on June 2, 2025. Starting from late 2025, GIA will cease using the traditional 4Cs grading system (Cut, Color, Clarity, Carat) for lab-grown diamonds, which is designed for natural diamonds, and will instead adopt a new descriptive rating system.
Lab-grown diamonds submitted for grading will only receive broad ratings of “Premium” or “Standard,” with diamonds of excessively low quality not being graded. This landmark change signifies a historic turning point for the global diamond industry: it not only redefines the perception of value for lab-grown diamonds but also marks the formal institutionalization of the distinction between natural and lab-grown diamonds.
GIA’s move is not a simple terminology adjustment but a systematic effort to completely separate the evaluation systems for lab-grown diamonds from those for natural diamonds. As a non-profit scientific research institution, GIA clearly states that lab-grown diamonds and natural diamonds have fundamental differences in their formation methods, physical characteristics, and market value, and the two should not be conflated.
This adjustment by GIA to the grading standards for lab-grown diamonds is another milestone breakthrough following its previous shift in terminology—abandoning the use of “synthetic” and instead describing them in comparison to natural diamond standards. The original purpose of creating the 4Cs standard (Cut, Color, Clarity, Carat) was to help consumers understand the unique and complex qualities of natural diamonds. This reform of the grading system further highlights the core value of natural diamonds: natural scarcity and emotional attributes.
No two natural diamonds are exactly alike; each natural diamond is unique and irreplaceable, possessing distinctive growth patterns, inclusions, and colors formed over billions of years underground. These natural gemstones, formed over immense periods deep within the Earth, are considered a unique luxury category due to their beauty, rarity, and non-renewability. They are also seen as symbols of preciousness and permanence, associated with human-pursued virtues and emotions such as love, commitment, and eternity. Simultaneously, natural diamonds bear industry responsibilities for social and environmental impact, with their mining and trade generating economic revenue and social welfare for many countries and regions, improving local living conditions and education levels, and promoting social peace and stability.
In contrast, lab-grown diamonds are mass-produced using High-Pressure High-Temperature (HPHT) or Chemical Vapor Deposition (CVD) technologies, resulting in highly uniform characteristics. Their industrial nature makes it difficult for them to carry the multiple values of natural diamonds in terms of emotion, scarcity, investment, and heritage. GIA’s reform not only reaffirms the benchmark status of natural diamonds for authenticity, value, and irreplaceability but also clearly states that while lab-grown diamonds have a market space, they should no longer be defined by the evaluation logic of natural diamonds. The market needs to stop conflating them with natural diamonds.
For a long time, some lab-grown diamond merchants have used marketing language such as “sustainable” and “equitable,” which can confuse consumers and downplay the essential differences between lab-grown and natural diamonds. As an institution committed to maintaining the credibility of the gem and jewelry industry, GIA’s move ensures that consumers can make informed choices without being misled by false equivalency concepts, further protecting consumers’ rights to information, choice, and fair trade. At the same time, by ceasing to use the 4Cs standard for lab-grown diamonds, GIA reaffirms its commitment to scientific integrity, public transparency, and the fulfillment of its founding purpose.
GIA’s grading reform is bound to have a profound impact on the global jewelry industry. With the official announcement of this change set to take effect by the end of 2025, it is expected that major testing institutions worldwide will follow suit. The value boundary between natural diamonds and lab-grown diamonds is being clearly defined and distinguished by GIA through institutional and standard-setting measures.
