Diamonds Forged in Plasma

For decades, we have been promised lab-grown diamonds that are brilliant, affordable and free from the environmental pitfalls of diamond mining. But their makers have struggled to deliver quality stones at scale. The Diamond Foundry has an edge: its new hydro-powered plasma reactor in Wenatchee, Wash., constructs diamonds using a fraction of the energy of other methods, including mining. As a result, the facility can churn up to 1 million carats of diamond every year, enough for nearly 500,000 average-size engagement rings. That speed, the company says, makes it possible for lab-grown diamonds to be cost-effectively produced at mining scale for the first time. Diamond Foundry stones (which range from a few hundred dollars to more than $30,000) are gem-quality, and the company recently partnered with Apple’s Jony Ive to create an all-diamond ring to raise money for charity. —Justin Worland