Heartwood can vary from pale yellow to a light, muted reddish brown; sapwood is grayish-white. There are many species of Birch, worldwide; it is one of the most popular woods, ironically, for both veneer and utility applications. Figured pieces are the more desirable for veneer, with wide, dramatic curly figuring (similar to Cherry) decorating the surface.
American Birch works easily -- it turns, glues and finishes well -- although most boards have very little natural luster. It's a versatile wood that can be used for a number of different applications, but it needs to be protected, as the wood will decay when exposed to the elements. (... and if left unprotected will rot.)