How Lab-Created Moissanite Is Made: The Complete Science Step by Step

Moissanite is one of the rarest minerals in nature — so rare that all moissanite used in jewelry is lab-created. But how exactly is moissanite made? The process of growing silicon carbide crystals large enough and pure enough to be cut into gemstones is a remarkable feat of materials science, combining high-temperature crystal growth, precision cutting, and rigorous gemological grading. Here's the complete step-by-step science of how lab-created moissanite is made.

Step 1: The Raw Materials — Silicon and Carbon

Moissanite is silicon carbide (SiC) — a compound of silicon and carbon. Both elements are abundant in nature: silicon is the second most abundant element in Earth's crust (after oxygen), and carbon is the basis of all organic chemistry. The raw materials for moissanite production are therefore widely available and inexpensive — a stark contrast to diamond mining, which requires extracting rare carbon deposits from deep within the Earth.

The silicon and carbon used in moissanite production are refined to extremely high purity before use. Any impurities in the raw materials can affect the color and clarity of the resulting crystal.

Step 2: Crystal Growth — The Lely Method and Its Derivatives

The primary method used to grow large, gem-quality silicon carbide crystals is a derivative of the Lely method, originally developed by Jan Anthony Lely in 1955. The modern process used for gem-quality moissanite production is called Physical Vapor Transport (PVT) or Modified Lely Method:

The growth chamber: Silicon carbide source material is placed in a graphite crucible inside a high-temperature furnace. The furnace is heated to approximately 2,000–2,500°C (3,600–4,500°F) — temperatures that exceed the surface temperature of the sun.
Sublimation: At these extreme temperatures, the silicon carbide source material sublimes — it transitions directly from solid to vapor without passing through a liquid phase.
Crystal nucleation and growth: The silicon carbide vapor migrates through the growth chamber and deposits on a seed crystal (a small piece of silicon carbide) at the cooler end of the chamber. Over days or weeks, the crystal grows layer by layer as silicon carbide vapor continues to deposit on the seed crystal.
Growth rate: Gem-quality silicon carbide crystals grow at approximately 1–5mm per hour under optimal conditions. A crystal large enough to yield multiple gem-quality stones may take several days to grow.

Step 3: Crystal Inspection and Selection

After growth, the silicon carbide boule (the large crystal produced by the growth process) is removed from the furnace and inspected. Not all boules are suitable for gem-quality moissanite — inclusions, color variations, and structural defects can disqualify portions of the crystal. Gem-quality sections are identified and marked for cutting.

Step 4: Cutting and Shaping

Cutting silicon carbide is significantly more challenging than cutting most gemstones because of its extreme hardness (9.25 Mohs). Diamond-tipped cutting tools are required. The cutting process involves:

Orientation: The crystal is oriented to maximize the yield of gem-quality material and to align the crystal's optical axis for optimal brilliance.
Sawing: The boule is sawn into slabs using diamond-tipped saws.
Preforming: The slabs are cut into rough stone shapes (preforms) that approximate the final gem shape.
Faceting: The preforms are faceted on diamond-impregnated lapping wheels, with each facet cut to precise angles to maximize brilliance and fire. A round brilliant moissanite has 58 facets, each cut to within fractions of a degree of the ideal angle.
Polishing: The faceted stone is polished to a mirror finish on progressively finer diamond-impregnated polishing wheels.

Step 5: Quality Control and Grading

After cutting and polishing, each moissanite stone is inspected and graded for color, clarity, cut, and carat weight equivalent. Stones that meet the standards for DEF color (colorless) and VVS1 clarity are selected for GRA certification. The GRA (Gemological Research Association) issues a certificate for each stone, documenting its color grade, clarity grade, cut grade, and measurements.

Step 6: Setting and Finishing

The graded and certified moissanite stones are then set in jewelry by skilled craftspeople. The setting process involves selecting the appropriate stone for each piece, setting the stone in the metal mounting, and performing final quality control inspection before the piece is packaged and shipped.

The entire process — from raw silicon and carbon to finished, GRA-certified moissanite ring — takes weeks to months, involves temperatures exceeding 2,000°C, and requires precision at every step. The result is a gemstone that is chemically and physically identical to natural moissanite, with optical properties that exceed those of diamond.

Explore our collection — every stone DEF color, VVS1 clarity, GRA-certified, and backed by our Lifetime Gemstone Warranty.

Related guides:
The Science of Silicon Carbide
How Is Moissanite Made?
How Moissanite Is Graded Inside the GRA Lab
Is Moissanite a Real Gemstone?
Moissanite vs Diamond Under the Microscope