How CVD Lab Grown Diamonds are made

Lab-grown diamonds for your dream engagement ring in Melbourne 

CVD (Chemical Vapor Deposition) is the most advanced method of growing diamonds in a laboratory. It’s a process that mimics how diamonds are naturally formed in interstellar gas clouds, using a real diamond seed and a carbon-rich atmosphere to grow a diamond atom by atom.

In this article, we explain exactly how CVD diamonds are created, from seed to finished rough, and why the process results in the most beautiful diamonds available for your engagement ring in Melbourne.

What is a CVD Lab-Grown Diamond? 

A CVD lab-grown diamond is a diamond grown in a controlled laboratory environment, rather than a stone formed over billions of years through natural geological processes. A CVD diamond begins its life as a diamond seed inside a sealed vacuum chamber, engineered to replicate the precise conditions needed for pure carbon to form layer by layer to create a real diamond. 

Chemically, physically, and optically, the result is a genuine diamond. The only difference is where and how it was grown. Every CVD Type IIA diamond passes as a genuine diamond under gemological testing, sharing the same hardness and brilliance. Certified lab-grown diamonds are laser-inscribed with “LG” on the girdle of the stone, clearly identifying them as lab-grown for full disclosure to the buyer.

The CVD Process, Step by Step

CVD is the newest and most advanced method of growing diamonds, and it works in a way that mimics how diamonds are believed to form in interstellar gas clouds rather than replicating earth's natural conditions.

1. Starting with a perfect seed

Every CVD diamond begins its life as a fragment or thin slice cut from a real Type IIA diamond. Type IIA diamonds are exceptionally rare, making up only 1-2% of all mined diamonds worldwide. They are coveted for having no nitrogen impurities, minimal imperfections, and outstanding colour clarity. This sliver of a diamond becomes the "DNA" for the new stone and because the seed is already a diamond, everything grown from it inherits that same premium structure.

2. Inside the vacuum chamber

The diamond seed is placed inside a sealed vacuum chamber. Carbon-rich gas is then introduced into the chamber, and the environment is heated to between 700–1300°C.

3. Layer by layer diamond growth

Inside the chamber, the carbon gas is broken down and the purest carbon atoms are drawn to the diamond seed, bonding to its surface one atomic layer at a time. This slow, controlled growth is what gives CVD diamonds their exceptional internal structure, and identical brilliance to a natural diamond.

4. Weeks of patience for perfection 

This process takes between 4 and 8 weeks for the diamond rough to fully form. Depending on the intended carat weight and proportions required from the diamond. Over this time, the stone gradually grows into a cubic-shaped rough, ready for faceting and polishing. To be masterfully cut into their destined diamond shape.

Why the Diamond Seed is Important

The quality of a CVD diamond is directly tied to the quality of its starting seed. Because CVD diamonds are grown from an actual slice of a Type IIA diamond, they inherit that seed's purity from the very first atom. This is why CVD diamonds are consistently the whitest and brightest lab-grown diamonds available, as they're grown from the best possible foundation.

HPHT diamonds take a very different path, starting from a graphite seed combined with a molten metal flux of iron, nickel, and cobalt. This metal exposure is why around 85% of HPHT diamonds are magnetic and prone to metallic inclusions, a key marker gemologists use to identify them.

A More Sustainable Process

Beyond producing superior stones, CVD is also the more sustainable choice. The process requires lower temperatures and smaller chambers than HPHT, which needs enormous, purpose-built facilities to withstand extreme pressure. This translates to less energy consumption, less waste, and a smaller environmental footprint overall, while also giving growers far greater quality of the final result.

What This Means for Your Diamond

When you choose a CVD Type IIA lab-grown diamond, you're choosing a stone with the purest possible origin, grown through the most controlled and best process available today. A CVD lab-grown diamond is chemically identical to a natural diamond, indistinguishable to the naked eye. Not every lab-grown diamond on the market is held to the same standard. Understanding the difference between CVD and HPHT and asking your jeweller which process was used, is the best way to ensure you're getting the quality you're paying for.

At JANAI, our diamond specialists can guide you through our extensive range of CVD lab-grown diamonds available for your custom engagement ring, so you can choose with total confidence in what you're getting.

Begin your dream ring journey with JANAI Jewellery.

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