Is my Bella Boo a Yorkshire Terrier or a Silky Terrier????

Doesn't really matter, she's cute as can be, but I'm trying to settle a dispute between two of my friends, and I really don't know for sure, because she's a rescue. She's just over 9 lbs, and is longer than she is taller, but none of that really means anything, and when I look at pictures comparing the two, I can't tell the difference.
I do have pictures in my photo album : )