Lab grown or natural?

Are lab grown diamonds real diamonds?

Yes. A lab grown diamond is carbon in the same crystal structure as a mined one, with the same hardness, the same refractive index and the same optical behaviour. It is not a simulant. Cubic zirconia and moissanite are different materials that look diamond adjacent; a lab grown diamond is a diamond that was formed in a machine instead of underground.

The Federal Trade Commission revised its jewelry guides in 2018 to reflect this, removing "natural" from its definition of a diamond. A seller may not imply that a lab grown stone is fake, and equally may not sell one without disclosing that it is lab grown.

How the two are actually made

Natural diamonds formed in the mantle over timescales measured in the hundreds of millions to billions of years, then arrived near the surface in volcanic rock. Lab grown diamonds are produced in weeks by one of two methods.

• HPHT, high pressure high temperature, reproduces mantle conditions around a small diamond seed.
• CVD, chemical vapour deposition, grows the crystal a layer at a time from carbon rich gas in a vacuum chamber.

Both produce gem quality material. Neither method is inherently better, and the growth route is not something a buyer needs to choose between; it appears on the grading report and has no bearing on how the finished stone looks.

What a lab grown diamond costs compared to a natural one

A lab grown diamond costs substantially less than a natural one at the same cut, colour, clarity and carat, and the gap has widened as growing capacity has increased. That is the whole of the price story, and any more precise figure would be out of date quickly.

This is why Astra Jewelers sets the two side by side at matching specification rather than quoting them separately. Seeing a natural stone and a lab grown stone of the same grade next to each other, with both prices, is the only comparison that answers the question for your budget rather than in the abstract.

The practical consequence is that the same budget buys a visibly larger or better graded stone if you choose lab grown. Whether that trade is worth making is the next section.

Resale, insurance and holding value

This is the real difference, and it is the one most comparisons skip. Natural diamonds have an established resale market. Lab grown diamonds largely do not, and because production cost continues to fall, a lab grown stone bought today is unlikely to hold its price.

For an engagement ring that is going to be worn rather than traded, that may not matter at all. For a purchase being made partly as a store of value, it is the entire decision. Insurance also follows replacement cost, so a lab grown stone is cheaper to insure.

Which should you choose?

Choose lab grown if the priority is size or grade for the money, and the piece is being bought to wear. Choose natural if origin and rarity matter to you, or if resale value is part of the decision. Both are real diamonds and neither choice is a compromise on how the finished ring looks.

Astra Jewelers stocks and sources both, and has no reason to push either. The studio in Upper Montclair will show you the two at matching specification, with the certificates, and explain the trade in front of the stones rather than over the phone.

What to check before you buy either

• Ask for the grading report, and check it is from a recognised laboratory. GIA and IGI both grade lab grown stones.
• Check the report number is laser inscribed on the girdle, and ask to see it under magnification.
• Confirm in writing that the stone is lab grown or natural. Disclosure is required, so a seller who is vague about it is the problem.
• Compare at the same four grades. A lab grown stone one colour grade lower is not a like for like comparison.
• Ask what happens if you want to upgrade or reset later, which is where the resale difference shows up in practice.

Common questions