An unusual and fascinating colour to be found in a tube of oil paint.
It is a mid-tone warmish grey, the main benefit of this over a palette mixed grey is that it will be cleaner, and I can see it being useful in taking down the chroma a notch in skin tones and similarly in landscapes. A great colour to experiment with.
Pigment - Titanium Dioxide, PW6.1
Vehicle - Linseed Oil, Consistency - Buttery
I generally mix everything from a smaller set of key colors, but I have found this so useful that it makes sense to buy it in tubes. First, it's a very good gray as it is. That means I can often adjust it slightly rather than use it in a mix with other colors to get what I want. However, when mixing, it is often one of two or three basic colors such as raw umber that I include in mixing paint for soil and sky. Being titanium, it is opaque, so I go elsewhere if I want a transparent gray.