Hyperdiamond

Fighting his fatigue — it was a black slick lapping at his consciousness — Vargovic said: "I understand perfectly well. I have the samples of hyperdiamond, in my hands..."

Source: wiktionary

In 2005 scientists at Bayreuth University in Germany created a new material by compressing pure carbon under extreme heat. It’s called hyperdiamond or aggregated diamond nanorods (ADNR) and, although it’s incredibly hard, it looks rather like asphalt or a glittery black pudding.

Source: wiktionary

There are harder substances than diamond - In 2005, physicists Natalia Dubrovinskaia and colleagues compressed carbon fullerene molecules and heating them at the same time to create a series of interconnected rods called Aggregated Diamond Nanorods (ADNRs or "hyperdiamond"). It's about 11% harder than a diamond.

Source: wiktionary

Technically, hyperdiamond (diamond nanorod, DNR) is regular diamond, it's just been arranged into an optimal lattice.

Source: wiktionary