For once Pantone's description is quite muted. Ultramarine is simply described as being a deep, cooling blue green. It's far more than that. I think it's more vibrant than cooling with the richness of malachite.
In Pantone's preview Charlotte Ronson describes her signature colour as 'representing the richness of a bohemian lifestyle.'
As usual, here's a selection from Etsy to make you want more.