The Real Diamond Experts at Bremer Jewelry want you to be confident in your diamond purchase, especially when it comes to making a choice between earth-grown and lab-grown diamonds. In order for you to be confident, you need to be educated. So, class, take your seats quiet down [clap, clap – clap, clap, clap]. It’s time to learn everything you need to know about lab-grown diamonds!

Earth-grown diamonds and lab-grown diamonds share almost all of the same physical, chemical, and optical characteristics. To the naked eye, they are identical. So what’s the difference? The biggest difference between natural, earth-grown diamonds and lab-grown diamonds is the creation process and the resulting rarity. Let’s start by taking a look at each process and the impact it has on the growth and rarity of each diamond:

How are lab-grown diamonds made?

Sometimes referred to as cultured, created, or synthetic, lab-grown diamonds are created in laboratories through artificial, accelerated processes. There are two ways to create a lab-grown diamond: High Pressure High Temperature (HPTP) and Chemical Vapor Deposition (CVD). CVD is the preferred way to create the highest quality gems, so we’ll focus on this process. First, tiny pieces of diamond (rather like seeds) are put into a reactor filled with methane gas and hydrogen plasma.

The plasma is heated to 4000 Kelvin (over 6000 degrees Fahreinheit) and the seed is bombarded with carbon atoms.

The activated carbon-hydrogen species attaches itself the seed. Atom by atom the diamond crystal grows and after 400-500 hours you have rectangular shaped gems that are sent to a diamond cutter for cutting and polishing.

Rough (uncut) lab-grown diamonds created by Chemical Vapor Deposition (CVD)

Diamonds have been created in laboratories since the 1950’s for industrial applications. Recent improvements in technology have made it possible to produce en masse flawless, colorless stones that to the naked eye are identical to earth-grown diamonds.

How do earth-grown diamonds form?

Also known as mined or natural diamonds, earth-grown diamonds are stones that have formed naturally within the earth.

The occurrence of natural diamonds is remarkable because of the extreme rarity of the conditions necessary for their formation. First there needs to be the right environment. Certain areas of the earth’s mantle (100 miles below the surface), provide such an extreme environment: pressures higher than 40 thousand atmospheres (4 GPa) and temperatures of 950–1400ºC (1742-2550ºF).

Then you have to have the right ingredient: free species carbon, of which there is a relatively low abundance in the earth’s mantle.  Then lots and lots of time is needed to create these rare stones in the earth. It takes 1 billion to 3.3 billion years of heat and pressure to turn that free species carbon into diamond.

And finally, once diamond deposits have formed, a natural carrier is needed to bring the deposit to a mine-able depth. Kimberlitic eruptions (basically volcanic eruptions that form deep in the mantle) have served this purpose by tearing out pieces of the mantle and carrying them rapidly toward the surface.

Kimberlitic volcanism is unique and rare (an eruption has never been witnessed – most occurred millions of years ago) and are only found in the oldest, most stable continental crust environments (geology.com). The journey of an earth-grown diamond is long, fascinating, and yes, rare. To look at a natural diamond and know that it’s journey began deep inside the earth over a billion years ago is awesome, indeed.

Earth-grown rough (uncut) diamonds.

Does the growth method actually affect the diamond?

Yes. The way a mineral forms helps determine its identity.

Manufactured diamonds are grown over a very short time—just a few weeks—under conditions different from natural diamond formation deep in the earth.  These diamonds correspond to types Ib, IIa, and IIb –  categories not often found among natural diamond. Type Ib diamonds contain scattered and isolated nitrogen atoms that are not in pairs or clusters. Type IIa diamond contain almost no nitrogen, and IIb diamond contains boron.

The vast majority (over 95%) of earth-grown diamonds are what scientists call type Ia. The great age of these diamonds means that the nitrogen impurities have had time to aggregate into pairs or clusters. This kind of diamond cannot be grown artificially. 

The environmental differences in the creation of lab grown diamonds produce distinctive growth patterns that can be detected.

Idealized crystals (from left to right): CVD synthetic, HPHT synthetic, and natural diamond. Octahedral faces are shown as yellow and cubic faces blue. Most natural diamonds grow as octahedra (right), but HPHT synthetics (center) typically show a combination of cubic and octahedral faces. Octahedral faces are completely absent in CVD synthetics (left). Directions of crystal growth are shown by arrows. Dotted lines represent the position of the seed crystal in the HPHT synthetic diamond and the edges of the crystal in the CVD synthetic. (gia.edu)

Will lab-grown diamonds retain their value?

We cannot predict the future, but based on the past, they probably won’t. Whenever something can be massed produced (and advances in technology make it cheaper to produce), it’s value generally goes down. Take, for instance, flat screen TV’s.  Sharp and Sony introduced the first 42″ flat screen televisions in 1997. These models sold for over $15,000. Today, just 20 years later, Sony sells 60″ Ultra HD Smart flat screen TVs well under $1,000.

Rarity is the key factor is determining and maintaining value. As technology allows for a greater influx of lab grown diamonds into the market, their value will likely decline. The laboratory process allows for controlled, flawless color and clarity, one just like the next. But because lab grown diamonds can be produced en masse, they cannot realistically be considered rare or particularly valuable.

How can you tell if a diamond is lab-grown?

YOU can’t. But WE can.

Because the long-term value of lab-grown diamonds cannot be guaranteed, it is super important to us, your trusted family jeweler, that you know what you are purchasing!

To the naked eye, lab-grown and earth-grown diamonds of the same color and clarity may look the same. As lab-grown diamond quality continues to improve, it’s becoming more challenging to separate them from natural gems using standard equipment. Special (and expensive!) verification instruments must be employed to differentiate lab-grown from earth-grown diamonds.  The gem lab at Bremer Jewelry has been using a lab-grown scanner for the last two years to ensure that any diamonds we acquire without proper certification are indeed rare, earth-grown diamonds.

Nate, Bremer’s own certified gemologist, scans melee diamonds to determine whether they are lab-grown or earth-grown.

Lab-grown diamonds show a different surface fluorescence. Diamond fluorescence is the visible light that a diamond emits when it is exposed to the UV rays (gia.edu). When you stand under a blue light or ultraviolet light, sometimes you can see your whites get brighter or your teeth appear to glow. This is the same effect the diamond has under the UV rays. Type IIa diamonds fluoresce blue while diamonds grown using lab processes fluoresce any color other than blue, namely red and orange.

One lab-grown melee shows bright red in a tray full of earth-grown diamonds, which fluoresce blue. New advances in technology allow our gemologist to scan diamonds in their settings as well!

Remember that an honest lab-grown manufacturer will often inscribe their diamonds for easy identification. Also, any reputable jeweler will provide GIA certification for any earth-grown diamond they sell.

New advances in technology allow our gemologist to scan diamonds in their settings as well!

Are lab-grown diamonds eco-friendly?

The fact that lab-grown diamonds don’t need to be torn out of the earth certainly makes them seem environmentally friendly, but truth be told, the jury is still out on this popular claim. Consider the fact that lab-grown diamonds are made in factories which require massive amounts of energy to produce them. Additionally, accurate information on the materials used to make lab-grown diamonds have not been released on these often-proprietary processes.

Also consider that many diamond mining companies go to great lengths to preserve the environment and improve the communities surrounding their mines. In many, many cases, these are in poor countries where people rely on the jobs and education provided by the mining company.  No company or process is perfect, but have a look at what companies like Forevermark are doing to help the environments and communities their mining impacts. Many of their programs have an eye on the future – the future of the land and it’s people, even after the mine is “dried up” and gone. If environmental friendliness is a factor in your diamond purchase decision, we highly encourage you to read, research, and stay up-to-date on the latest industry news!

Which diamond is best for me?

Your decision to purchase a lab-grown or earth-grown diamond depends may depend on many things. Everyone is different and cost, quality, availability, rarity, and origin story may have varying levels of importance to different people. Our job as your trusted jeweler is to make sure you are informed and can make an educated decision. Regardless of which type of diamond you are shopping for, your Real Diamond Experts at Bremer Jewelry have the experience, knowledge, and technology to help you make your purchase with confidence. We welcome you to stop by either of our stores, meet with one of our jewelry consultants, and experience for yourself what a difference it makes to shop with the family at Bremer Jewelry!

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