I absolutely love this colour. It's such a unique colour and is one of the few pink shades that works with my skin tone. I would probably describe it being like a berry pink, like a pink with a slightly deep purple tone to it. It's super pigmented and takes a little extra work to remove due to all that lovely colour. As I said, I couldn't seem to capture the colour properly so I would say the colour is a little deeper in person, not quite as fushia. Like Copacobana the matte effect has a slight sheen to it.
You can find Rhossili along with all the other Barry M Mattes at Boots and Superdrug.