Diamonds Are for Softies - Boron is Harder

I have read that there are some rare earth nitrides that are even harder.

Did I miss something? After reading the article, I see no evidence that "Boron is Harder"; only that some Boron-Nitrogen compounds MIGHT be harder (with "Hardness" undefined) under certain conditions. Until someone unequivocally demonstrates production of a Boron structure which will, say, indent diamond but not vice-versa, or one which can readily cut diamond, I will remain skeptical of this headline.

I understand the reasons why a search for harder materials is needed, and what advantages may accrue to materials capable of cutting / abrading iron and steel without being dissolved into it like diamond is, but I suspect that any such material will have its own Achilles' Heel for some uses.