Sandstone. Was this an attempt to recreate the fabled "Curdled Ivory?" I don't know.
This is, in fact, a little darker and browner than the Effetre Ivories - and browner too than the Vetro Dark Ivory. Given that I luuuv ivory - I'm happy enough to have a fifth shade in that colour set - although I can appreciate that some folks may not see a point to it. It is a warmer, streakier colour.
And - you can see from the turquoise dots - it also shares the ivory/turquoise copper/sulfur reaction.