I believe the correct answer is C. Copley.
Portrait d'apparat— a Rococo technique of portraying the
subject with objects associated with him in his daily life—was used by American
painter John Singleton Copley, whose portraits and historical subjects are generally
acclaimed as the finest artist of colonial America. The use of Portrait d’apparat
gave his works liveliness and acuity which was not usually associated with
XVIII century American painting.
The color is called streak which is the color of the mineral in powder form. :)
