In case you aren't able to see/access my earlier response to this question, I'll re-post it:
"The mirror was from Room & Board, but it has since been discontinued and is no longer available. Too bad, as it was a nice, minimalist design...."

Hi Susan, My cabinet guy here in Asheville is making the vanity and mirror based on this picture! He put some type of material on the vanity to make it shiny (not the boat finish) and it looks great. Would you leave the wood in the mirror matted or put the high-gloss finish on it too?
THANKS!

Personally, I always prefer a matte finish on wood - the wood portion on the mirror from my room design was a matte finish (we custom stained the Room & Board mirror, as the colors that were offered weren't exactly what I was looking for). The cabinet actually has a Satin protective finish applied - the lighting in the photo makes it appear shinier than it really was. But it's all a matter of personal preference!

Could you tell me what size the mirror is?

Unfortunately, no. This project was done several years ago and that mirror is no longer available from the manufacturer. I remember that the vanity cabinet/room wall-to-wall was 3', so looking at the photo, I would estimate the mirror to be approx. 18" x 24".