Swidb consulted with a street cook who stated the characteristics in the original post exhibit the properties of niacinamide (vitamin B3). Due to the ease of crystalazation it is becoming the "cut" of choice of many street cooks. He also commented the residue from a foil burn test mimics meth so closely some street dealers are selling pure cut.
If you need more info:
http://www.aonevitamins.com/powdered_vitamins_powdered_vitamins_niacin.htm (http://www.aonevitamins.com/powdered_vitamins_powdered_vitamins_niacin.htm)