What can I say this is an amazing brand of products first of all, NARS really lays down the line when it comes to all of their products, they are great quality, pigmentation, and packaging. As for the price many may agree they are a little steep. With one blush running for a whopping $26.00 (US) wow!!! But I personally must admit you do get your money's worth.
COLOR / PIGMENTATION: As for the Mata Hari blush it self the color is amazing to this date I personally have yet to encounter any close matched dupe for it, this soft nude matte pinky mauvey (no shimmer/no sheen) color is so beautiful when applied just ever so slightly on the cheeks, all though if you prefer a more buildable color as well this will totally get the job done w/o to much work, blends great and with a nice soft subtle highlight applied over the tops of the cheeks it would amplified this color even more. Great applied lightly for light to medium skin tones,and beautiful as well when applied a little more builded on darker skin tones.
BRUSH: I would personally recommend using a MAC 168 (or a comparable brush like one's from essence of beauty or sigma, coastal scents) basically any slanted soft white goat hair brush would work for application.
WHERE TO BUY / PRICE: $26.00 (US) @ Sephora (or Sephora.com) Nars.com, Beauty.com among others.
If you'd like any more details please message me and I will get back to you ASAP.