There are two broad ways to make a “fake” diamond: grow a real diamond in a lab (chemically identical to a mined one) or use a different material that looks like a diamond but isn’t. Both approaches are well established, commercially available, and far cheaper than pulling stones out of the ground. Lab-grown diamonds now cost 80 to 85 percent less than natural diamonds of the same grade.
The term “fake diamond” covers a lot of ground, so this guide breaks down the actual science behind each method, what you can realistically do at home (very little), and how each option compares in durability, appearance, and cost.
Lab-Grown Diamonds: Real Diamonds, No Mine
Lab-grown diamonds are not fake in the chemical sense. They’re pure carbon arranged in the same crystal structure as a mined diamond, with the same hardness (10 on the Mohs scale), the same refractive index (2.42), and the same thermal conductivity. The difference is origin: weeks in a machine instead of billions of years underground.
The first reproducible synthetic diamond was created on December 16, 1954, by engineer H. Tracy Hall at General Electric’s research labs. Hall placed diamond seed crystals into iron sulfide, packed everything into a graphite heater, and subjected it to about 1,600°C and 100,000 atmospheres of pressure. GE published the method in Nature the following year, and the diamond industry has never been the same.
Today, two commercial methods dominate.
High Pressure, High Temperature (HPHT)
HPHT mimics the conditions deep in Earth’s mantle. A small diamond seed sits inside a press that generates pressures of 5.0 to 5.5 gigapascals (roughly 50,000 times atmospheric pressure) at temperatures exceeding 1,600°C. Carbon dissolves from a source material and crystallizes onto the seed over a growth cycle that typically lasts about 12 days. Modern HPHT presses consume around 28 to 36 kilowatt-hours of energy per carat, making this the more energy-efficient of the two methods.
Chemical Vapor Deposition (CVD)
CVD works at much lower pressures but uses plasma to do the heavy lifting. A thin diamond seed is placed in a sealed chamber, and a mixture of hydrogen and methane gas is pumped in. Microwave energy (usually at 2.45 GHz) ignites the gas into a plasma, which breaks apart the methane molecules and frees individual carbon atoms. Those atoms drift down and bond to the seed, building up a diamond crystal layer by layer. Growth rates vary, but modern systems can add about 11.5 micrometers per hour for single-crystal diamond.
CVD is more energy-hungry, requiring anywhere from 77 to 215 kilowatt-hours per carat depending on the specific equipment and operating conditions. The tradeoff is flexibility: CVD can produce very large, very pure crystals with fewer metallic inclusions than HPHT stones sometimes contain.
Diamond Simulants: Looks Like a Diamond, Isn’t One
If you want something that sparkles like a diamond but don’t need the actual carbon crystal, simulants are the budget-friendly option. The two most common are cubic zirconia and moissanite.
Cubic Zirconia (CZ)
Cubic zirconia is zirconium dioxide, a completely different compound from diamond. It scores 8.0 to 8.5 on the Mohs hardness scale, which means it scratches more easily and will show wear over time. Its refractive index of 2.15 is lower than diamond’s, so it lacks the depth and brilliance of the real thing. CZ is extremely cheap to produce and is the material you’ll find in most costume jewelry. The main downside for daily wear is that it clouds and scratches within a year or two of regular use.
Moissanite
Moissanite is silicon carbide, and it’s a much closer competitor. At 9.25 on the Mohs scale, it’s harder than any gemstone except diamond itself. Its refractive index of 2.65 is actually higher than diamond’s, which gives it intense rainbow flashes of light. Some people love this “fire,” while others find it looks too flashy compared to a real diamond’s more balanced sparkle. Moissanite is durable enough for everyday rings and holds up well over years of wear, making it the preferred simulant for engagement rings on a budget.
Can You Make a Diamond at Home?
Short answer: not really. You may have seen viral videos claiming you can turn peanut butter, charcoal, or pencil graphite into diamonds using a microwave. While these materials do contain carbon, a diamond requires those carbon atoms to be forced into an extremely specific crystal lattice. That takes either industrial-scale pressure (tens of thousands of atmospheres) or plasma conditions that household equipment simply cannot produce.
A kitchen microwave operates at about 1,000 watts. A CVD diamond reactor uses specialized microwave generators running at 2.45 GHz with carefully controlled gas chemistry inside a vacuum chamber. The overlap between these two setups is essentially zero. At best, a home experiment might char your carbon source. At worst, you could damage equipment or start a fire. Scientists have converted unusual carbon sources into micro-diamonds in labs, but “lab” here means reactors capable of generating the necessary pressure and temperature, not a countertop appliance.
If your goal is to own a diamond-like stone without paying mined-diamond prices, buying a lab-grown diamond or moissanite online is far more practical than any DIY attempt.
How Experts Tell Them Apart
If lab-grown diamonds are chemically identical to natural ones, how does anyone know the difference? The answer is trace impurities and how the crystal grew.
Natural diamonds form over long periods deep underground and almost always trap clusters of nitrogen atoms during growth. These nitrogen aggregates classify most natural diamonds as “Type Ia.” CVD lab-grown diamonds, by contrast, grow so quickly and in such controlled conditions that they contain virtually no detectable nitrogen, classifying them as “Type IIa.” An infrared spectrometer can spot this difference instantly by looking at absorption patterns in the 1,000 to 1,400 wavenumber range.
Fluorescence patterns also differ. Under ultraviolet light, natural diamonds typically glow a uniform blue caused by nitrogen-related defects. CVD diamonds show a patchwork of colors: blue, orange-red, and purple-red in a mottled pattern that reflects their layered growth process. Gemological labs like GIA use these spectroscopic signatures to issue definitive identifications, but to the naked eye, a well-cut lab-grown diamond is indistinguishable from a mined one.
Simulants are easier to spot. Moissanite’s intense rainbow fire is a giveaway to trained eyes, and simple thermal conductivity testers can separate cubic zirconia from diamond in seconds (CZ conducts heat poorly by comparison).
Cost Comparison
The price gap between natural and lab-grown diamonds has widened dramatically. As of 2025, lab-grown diamonds sell for 80 to 85 percent less than equivalent natural stones. A one-carat natural diamond that might retail for $5,000 to $8,000 could have a lab-grown equivalent in the $800 to $1,500 range, depending on cut and clarity.
Moissanite is cheaper still, typically running $300 to $600 for a one-carat equivalent stone. Cubic zirconia is the bargain bin option at under $20 for a comparable size, though its poor durability means you may replace it often. The right choice depends on what matters to you: chemical authenticity, visual appearance, longevity, or simply price.
Energy and Environmental Tradeoffs
Lab-grown diamonds use significant energy but avoid the land disruption and water use of mining. HPHT production runs about 28 to 36 kWh per carat, roughly equivalent to running a window air conditioner for a day or two. CVD production is more variable, ranging from 77 kWh per carat in efficient commercial setups to over 200 kWh per carat in less optimized systems. Manufacturers increasingly power these processes with renewable energy to improve sustainability claims, though the industry is not universally green. If environmental impact matters to you, asking a retailer about the energy source behind their lab-grown stones is worth the conversation.