WHAT A GREAT COLOUR.
There are many versions of this colour out there, in all formats of paint. The one I use, and love, is Tri-Art's Finest Quality Liquid acrylic version. It is a combination of PBk 7 (carbon black), PB 15:3 (Phthalo Blue Green Shade) and PV 23 (Dioxazine Violet). My tendency is to use it in washes and glazes, so that the subtlety of its undertone is showcased. Such a beautiful neutral.
In this piece (acrylic skin), it has been washed over a base of Graphite Grey, Liquid Mirror and Interference Turquoise. There is also some dry brushing of Iridescent Bronze, Interference Blue and Zinc white. The base of the painting is gloss gel medium, with blocked in areas of Dry Media Ground.
For more information on Payne's Grey: http://painting.about.com/od/artglossaryp/g/defPaynesGrey.htm