How Big Can a Lab Grown Diamond Get? The 200 mm Single Crystal Diamond Explained (2026)

A lab grown diamond can now be grown as a single crystal 200 mm across: on November 6, 2026, Diamond Foundry announced what it calls the first D200mm single crystal diamond, the same diameter as a standard silicon wafer. It is a thin plate made for semiconductors and chip cooling, not a gem, but it shows how far diamond growth has come. Whether you read this over coffee in New York or anywhere else, here is the science behind the headline, explained simply.

What exactly was announced?

According to the company's press release, published on PR Newswire, the piece is a 200 mm (about 8 inch) diamond that is a single crystal, not an assembly of smaller pieces and not a polycrystalline wafer. The company describes it as a milestone for semiconductor and advanced technology substrates, with chip cooling for dense AI processors, high power electronics, optics and quantum systems among the intended uses. Its CEO, Martin Roscheisen, said the work makes a 300 mm version "predictable as well." These are the company's own statements, and the full details have not been independently published. For context, the same company announced a 100 mm single crystal diamond wafer in 2023, so the diameter has doubled in about three years.

Single crystal vs polycrystalline: why it matters

A single crystal is one continuous lattice: every carbon atom sits in the same repeating pattern from one edge to the other. A polycrystalline diamond is made of many small crystals, or grains, pressed together, each pointing a slightly different way. The boundaries between grains scatter light and heat.

• For heat: diamond carries heat about five times better than copper, but grain boundaries interrupt that flow. A single crystal keeps the path clean.
• For electronics: chip makers need a perfectly regular surface to build circuits on, which a single crystal provides.
• For light: a gem must be a single crystal too, which is why every diamond in a ring is one continuous lattice.

We explored the chip side of this story in why diamond is moving into computer chips.

How do you grow a diamond that large?

Large lab diamonds are grown by chemical vapor deposition, or CVD. Inside a vacuum chamber, a gas of methane and hydrogen is energized into a glowing plasma. Carbon atoms rain down onto a seed and attach to its lattice, one atomic layer at a time. The seed decides the shape of what grows: to get a wide single crystal, you need a wide seed with a perfectly ordered surface, and holding the plasma, temperature and gas evenly across the whole width is the hard part. The bigger the plate, the more ways it can crack, warp or form defects.

The other method, high pressure high temperature growth, copies the deep Earth with presses and molten metal, and grows chunky crystals rather than wide plates. Our explainer on CVD vs HPHT lab grown diamonds compares the two.

Does this change anything for diamond jewelry?

Not directly. A wafer is wide and very thin, built to sit under a chip, and nothing about it is cut for sparkle. A gem needs depth, so light can enter, bounce off the pavilion facets and return to your eye. What the news does show is that lab growth is now an industrial technology aimed at computing, which makes the difference between a lab crystal and a natural one even clearer. A natural diamond grew over geological time deep in the Earth and carries that history in its inclusions; a lab crystal is grown to a specification. Neither is fake; they are different stories. Our guide to natural vs lab grown diamonds walks through how to choose.

At Margaret Krinetz Fine Jewelry, handmade in Tel Aviv and shipped to New York, the diamonds we set are natural. The Diamond Studs carry 1.5 ct total of GIA certified natural diamonds in yellow gold, and the Wavy Bow Diamond Hoops hold approximately 1.85 ct of ethically sourced natural earth mined diamonds in 18K recycled gold.

The same carbon, a different scale

What I love about this story is the scale. The carbon in an 8 inch wafer and the carbon in a single star set stone on your finger is the same element, arranged in the same lattice. One is grown to move heat away from a processor; the other formed under enormous pressure and was carried up by the Earth. The physics is identical; only the purpose changes. That is the idea behind the Stellar Diamond Ring, with natural conflict free diamonds star set across an 18K gold band, like stardust on your finger.

If you want the cosmic side of that idea, read stars and diamonds are made of the same carbon.

Frequently asked questions

Is a 200 mm diamond wafer a gem?
No. It is a thin single crystal plate intended for electronics and cooling, not cut for brilliance.

Are Margaret Krinetz diamonds lab grown?
No. The pieces linked here use natural diamonds, as stated on each product page.

How long does delivery to New York take?
Every piece is handmade to order in 4 to 6 weeks, then shipped by DHL Express to New York in 3 to 5 business days, with free shipping over $1,500.

Did this change how you think about diamonds, natural or grown? Write to me, I love talking science with you.