While the Earth has kept steady with a single diamond-making process for millions of years, over the past few decades’ gemologists have been able to develop a few distinct methods for growing diamonds in a laboratory. And just as each method is different from the next, so is the diamond that is made. But what are these methods and how do the diamonds differ from each other? To help you better understand, here is a brief but helpful guide to the different types of lab-grown diamonds.

What Are The Different Types Of lab-Grown Diamonds?

There are two main types of lab-grown diamonds: Cultured diamonds and Simulant diamonds.   

Cultured Diamonds.

Cultured diamonds are lab-grown diamonds that are identical to natural diamonds. They are made with carbon, the raw material that natural diamonds are made from; as a result, their chemical, physical, and optical properties are the same as natural diamonds. To the naked eye, it is impossible to tell the difference between a lab-grown diamond and a natural diamond; only a diamond professional using special equipment can tell the difference.

There are two types of cultured diamonds: HPHT diamonds and CVD diamonds. The titles HPHT (High Pressure High Temperature) and CVD (Chemical Vapour Decomposition) refer to the processes used to make the diamonds.

1. CVD Diamonds.

A CVD diamond is a grown in a vacuum chamber. First, a diamond seed—a tiny splinter of natural diamond—is placed in the chamber. Second, the chamber is filled with carbon-rich gas. Last, the temperature inside the chamber is raised to over 800 degrees Celsius. This extreme temperature causes the gas to change to plasma, which releases carbon pieces. Over a few weeks, these pieces attach themselves to the diamond seed, eventually forming the diamond.

2. HPHT Diamonds.

A HPHT diamond, meanwhile, is grown in a press machine. Again, this method begins with a diamond seed. The seed is placed in the machine and then placed under both heat and extreme pressure. This causes the carbon to melt and attach to the seed. And just like the CVD method, after a few weeks a diamond is formed. The process for making HPHT diamonds is closest to the natural process for making diamonds.

Of the two types of cultured diamonds, HPHT diamonds are typically preferred over CVD diamonds. The conditions needed to make HPHT diamonds are easier to control than those needed to make CVD diamonds, which typically means they are more durable and hold their value better over time.

Simulant Diamonds.

As opposed to cultured diamonds, simulant diamonds have different chemical, physical, and optical properties to natural diamonds. They do, however, have the same gemological properties as natural diamonds. Simulant diamonds are often referred to as imitation diamonds.

There are three types of simulant diamonds: Cubic Zirconia simulants, Diamond Nexus simulants, and Moissanite Lab-grown Gemstones.

1. Cubic Zirconia Simulants.

A Cubic Zirconia simulant is made from reacting zirconium dioxide and mainly resembles a diamond crystal. These are the cheapest simulant diamonds and are not long-lasting.

2. Diamond Nexus Simulants.

A Diamond Nexus simulant is made from a mixture of carbon and other substances. They are more popular and more durable than a Cubic Zirconia simulant.

3. Moissanite Lab-grown Gemstones.

A Moissanite Lab-grown Gemstone is grown from silicone and carbon.

While simulant diamonds lack the quality, durability, and prolonged value of cultured diamonds, they are still a popular choice for people. For example, costume designers for the Film, Theatre, and Music industries typically use simulant diamonds as they are cheap to buy yet still have the same look as cultured or natural diamonds.