It was the sign of his office on Nostramo, and according to Zso Sahaal, provided him with comfort in his darkened dreams. The crown was made from adamantium that had been uncovered from the Night Haunter's impact into the planet's crust. It had a number of rubies and a single diamond contrasting against its obsidian frame. Eventually it would become the symbol of office of the Night Lords after Curze's death. Zso Sahaal, Curze's inheritor would seek this as would the Eldar, Imperium and Sahaal's rivals within the legion.
In Latin, Corona Nox translates to "the Night Crown".