LAB Grown Diamonds FAQ

Robert Goldstein
Aug 5
3 min read

Lab-Grown Diamonds

Lab-created, engineered, cultured, manufactured –

whatever name you know them by, lab-grown diamonds

are increasingly popular for all types of jewelry.

Learn about how lab-grown diamonds have gotten sparkle down to a

science and how they stack up against natural diamonds.

What Is A Lab-Grown Diamond

Lab-grown diamonds are diamonds that have been “grown” in a controlled laboratory setting. They’re comprised of the same chemical components you'll find in natural diamonds (carbon atoms arranged in a specific pattern) but instead of being formed deep in the earth’s crust, lab-made diamonds are created in a laboratory. Because lab-grown diamonds are chemically the same as natural earth made diamonds, they are virtually indistinguishable in terms of appearance, quality and durability.

Lab-grown diamond technology for industrial uses has been around for over 50 years, but within the last decade there have been impressive developments in quality and price, meaning these lab-grown stones can now be used in jewelry, too.

In CVD lab diamond creation, the small seed diamond is placed into a plasma reactor chamber where a mixture of carbon-rich gases is added at a low pressure. Then, microwaves are used to heat the gases and generate plasma. As the temperature climbs over several thousand degrees, the gas molecules break apart which makes way for carbon atoms to bond to the seed one layer at a time. As the layers build, the CVD lab creation process produces a complete lab-grown diamond.

The HPHT method takes another approach to creating lab-made diamonds, following a controlled process that mimics the conditions in which diamonds form naturally. HPHT diamonds start with the same seed diamond, but things change from there. With HPHT diamonds, the seed is placed in a large mechanical press along with a carbon starting material. The press applies high pressure coupled with high temperatures, resulting in extreme conditions for the carbon starting material. The material’s carbon soon separates and finds its way to the cooler diamond seed, resulting in new layers of carbon forming to grow the lab-made diamond in size. This causes more layers of the lab-grown diamond to form. The seed diamond acts as a guide for the lattice of carbon that will soon become the completed lab-grown diamond, guiding the new layers of carbon to form a complete stone. This lab diamond process is closest to the conditions in which earth created diamonds are formed.

Both CVD and HPHT diamonds can take several weeks or months to be created in a laboratory. The exact amount of time will depend on the diamond’s size, color and additional features.

What Is The Difference Between Lab-Grown And Simulated Diamonds?

Unlike lab-grown diamonds, simulated diamonds are not diamonds. Diamond simulants such as cubic zirconia and moissanite have different chemical compositions compared to a diamond.

Simulants are made from seed materials like glass or cubic zirconia. This fact makes diamond simulants like moissanite lack the hardness and optical properties of lab-grown diamonds. As time goes on, simulants become much more susceptible to wear-and-tear and diminished sparkle. Lab-made diamonds, on the other hand, are chemically identical to natural diamonds and offer lasting beauty.

How Are Lab-Grown Diamonds Certified And Graded?

As with natural diamonds, diamonds made in a lab have the option to receive grading. After being sent to a gem institute that specializes in grading diamonds, lab-grown diamonds are graded independently by several of the lab's gemologists. Afterward, the individual grades are compiled and compared to give the lab-grown diamond its final grade.

Not all lab-grown diamonds are graded. Typically, smaller gems do not get grading, and not all jewelers choose to grade their lab-grown diamonds. At Blue Nile, we offer grading for many of our lab-created diamonds to bring transparency to the lab grown purchasing process.

Can You Tell The Difference Between Lab-Grown Diamonds And Natural Diamonds?

There typically aren’t distinguishable differences between manufactured and natural diamonds, especially when comparing them with the unaided eye. Both lab-created and earth created diamonds have the same crystalline carbon structure and offer the same optical qualities.

An expert jeweler may be able to tell the difference between these two kinds of diamonds when looking at their inclusions under magnification. They may have different types of inclusions depending on the diamond’s creation process.