A synthetic gemstone is a lab-created material that closely replicates the chemical, optical, and physical properties of its natural counterpart. In certain cases, such as synthetic turquoise or opal, additional compounds may be present.
Synthetic gemstones have been produced since the late 19th century, initially driven by industrial demand rather than jewelry. The first major success was the creation of faceting-quality synthetic ruby. Today, synthetic crystals are used in communications, laser technology, microelectronics, and abrasives. When crafted for jewelry, synthetic gems can be produced with consistent color and crystal shape, making them far less rare than natural stones of similar size, clarity, and color intensity. Due to their similarity to natural gems, strict regulations govern their marketing and sale.
In the United States, the Federal Trade Commission mandates clear disclosure of lab origin for any synthetic gem. Failing to provide this information throughout the distribution chain—from manufacturer to end consumer—is considered deceptive. Industry associations have also established guidelines to ensure proper disclosure at the point of sale. Over the last decade, fewer new types of synthetic gems have been introduced, suggesting the range of materials is nearing its practical limit, although production levels remain high.
Researchers have developed numerous laboratory methods to create synthetic gems, generally classified into two main categories: melt-based processes and solution-based processes.
Melt Processes:
The chemical composition of the melt matches that of the resulting crystal.
Flame Fusion: One of the earliest and most cost-effective methods, flame fusion involves dropping powdered chemicals into a high-temperature flame. The melted material falls onto a rotating pedestal, forming synthetic crystals. Commonly used for corundum and spinel.
Crystal Pulling (Czochralski Method): Nutrients are melted in a crucible, and a seed crystal is dipped into the melt. As the crystal slowly pulls from the melt, it grows. This method is used for alexandrite, chrysoberyl, corundum, and garnet.
Solution Processes:
Here, the solution or melt differs chemically from the resulting crystal. Dissolved constituents crystallize on a seed crystal as the solution cools.
Flux Growth: Flux, a solid material that melts and dissolves other substances, allows synthetic crystals like emerald, ruby, sapphire, alexandrite, and spinel to form gradually as the solution cools. This process can take up to a year and requires costly equipment, but produces high-quality results.
Hydrothermal Growth: Mimicking natural conditions deep in the Earth, this method uses heat and pressure to dissolve nutrients in water. As the solution cools, synthetic quartz crystals form. Hydrothermal growth is the only successful method for lab-grown quartz and is also used for certain beryls and corundum.
Common Synthetic Gems:
Diamond: Lab-grown diamonds share most characteristics with natural diamonds. Methods include:
Chemical Vapor Deposition (CVD): Carbon atoms precipitate on seed plates in a vacuum chamber.
High Pressure, High Temperature (HPHT): Diamonds form on seed crystals under extreme pressure and heat.
Corundum (Ruby and Sapphire): Can be produced through multiple methods, from affordable to high-end. Ruby was the first synthetic gem created in the 19th century. Sapphires have been made by flame fusion, flux growth, and hydrothermal methods, sometimes showing color-change or asterism effects.
Emerald and Other Beryls: Available in colors such as green, blue, yellow, and red. Flux and hydrothermal processes are used, with high-quality emeralds achieved through careful cultivation.
Quartz: Synthetic quartz, including amethyst, citrine, rose quartz, and smoky quartz, is widely used industrially for its piezoelectric properties in watches, clocks, filters, and communications devices.
Spinel: Early attempts to grow blue sapphire produced spinel by accident. Synthetic spinel is available in many colors and often substitutes for natural gemstones.
Opal: Lab-created opal replicates the play-of-color seen in natural stones, typically formed by precipitating microscopic silica spheres and consolidating them under pressure.
Alexandrite and Color-Change Stones: Synthetic alexandrite and color-change corundum or spinel are produced to meet demand when natural stones are scarce.
Over the years, experimental synthetic gems have been attempted, but many are rarely seen today due to abundant natural alternatives.
Lab Grown Emerald
