Lab-grown diamonds have surged in popularity. But not for the reason you might think.

I was having dinner with some girlfriends recently and asked them if they would ever consider lab-grown diamonds for an engagement ring. 

They both looked at me and replied without skipping a beat: "No."

It's a traditional way of thinking. I used to feel the same way before I learned more about them. 

Just before this recent conversation, I was invited to the Michael Hill HQ for an event about their jewellery recycling program (before I continue, nothing about this article is sponsored), but I couldn't help but fixate on their lab-grown diamonds. 

They looked exactly the same as natural ones.

Engagement ring trends through the decades. Post continues below.

In the past five years, the lab-grown diamond market has taken off.

Diamond industry analyst Edahn Golan recently said, "By May of this year, 50 per cent of loose diamonds sold by American jewellery retailers are expected to be lab-created diamonds."

The boss of one of the largest lab-grown diamond manufacturers boldly claimed that sales of lab-grown diamonds could eclipse sales of mined ones by 2030.

It was more than just the fact they are cheaper and better for the environment that interested me.

"To the naked eye, there is no clear distinction between the two diamonds," Claire James, Michael Hill's General Manager of Product and Buying told me.

So why aren't we buying or talking about them more? 

I asked Claire all the common questions people have about lab-grown diamonds to understand both the appeal and the hesitation. 

Here's what she told me.

OK, what actually are lab-grown diamonds?

"Laboratory-grown diamonds are classified as 'diamonds'," Claire told Mamamia. 

Some people refer to them as 'synthetic diamonds', but the broader jewellery industry uses terms like lab-grown or man-made diamonds to avoid giving consumers the (false) impression that they’re fake.

"They have essentially the same chemical, physical and optical properties and crystal structure as natural diamonds. 

"They also display the same level of hardness (10 on the Mohs scale of hardness, which is used to measure the relative hardness and resistance to scratching between minerals) and sparkle," she said.

And the manufacturing process is improving all the time. 

In 2016, lab-grown diamond company MiaDonna announced its partners had grown a 6.28 carat diamond, the largest created in the US at that point.

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The main difference between lab-grown diamonds and natural diamonds is their origin.

As the name implies, lab-grown diamonds are made in a lab with innovative methods, while natural diamonds are formed by the earth over millions of years and then mined.

They’re also cheaper. A lot cheaper.

These days, lab-grown diamonds typically cost around 30 to 40 per cent less than a comparable mined diamond.

And as technology improves and production ramps up, they're only going to get cheaper.

The difference between lab-grown, moissanite and cubic zirconia.

Did you think they were all the same? Me too! 

"Laboratory-grown diamonds are not to be confused with diamond simulants such as cubic zirconia or moissanite," Claire said. 

Moissanite is a gemstone made up of silicon carbide instead of carbon. Compared to diamonds, it's rated lower on the Mohs scale of hardness. 

It also creates a rainbow-like effect when it sparkles – diamonds simply display their famous sparkle – and is cheaper.

Cubic zirconia is also a common alternative to diamonds. 

The stone is completely manufactured in a lab, and unlike moissanite, cubic zirconia can be made completely colourless, making this stone on par with glass in terms to properties.

It's cheaper than both diamonds and moissanite, less durable and shines the least.

Why are couples choosing lab-grown over mined diamonds? 

"We believe laboratory-grown diamonds provide customers with an alternative option in the market," Claire said.

"Whether they are looking for something more affordable, or they are looking for a carbon-neutral or certified sustainable jewellery option – they know they can comfortably purchase a laboratory-grown diamond piece of jewellery that has the exact same characteristics that a natural diamond can offer."

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Claire explained that a lab-grown diamond is graded on the exact same characteristics as natural diamonds: cut quality, clarity, colour grade and carat weight.

If couples are choosing a mined diamond, they might have to compromise on one of the "C's", but if they choose a lab-grown, they can achieve the look they want for a lower price.

That's where they got me. 

So you're telling me, lab-grown diamonds are technically diamonds.

To the naked eye, nobody will notice the difference.

And you can get exactly what you want, cheaper?

No wonder they have surged in popularity.

Feature image: Mamamia/Instagram/@michaelhillj