Definately a silver black (aka silver dapple), and many of them DO have a brown look to them at times. If you go to my website (in my sig) and go to horses, mini horses, mini geldings (sorry I can't link to it from work) and look at Cruiser, he is DNA tested silver black... but nothing "black" about his looks! :) Silver blacks have a wide range of appearences.
The silver gene is a dilution gene and I have yet to see a silver that actually looked silver. I agree with everyone else that looks to be a black based silver or what most call "silver dapple". Very pretty!