Sometimes even experts have a hard time 'seeing' the difference between red oak and white oak. The only SURE FIRE way to know is to send a sample of your floor to a lab that does the testing for wood species. The test is about $100 and will prevent TENS OF THOUSANDS of dollars of heartache.

If you are getting mixed responses, I HIGHLY recommend you get a small sample cut and shipped to one of those labs. You will be VERY glad you did.

Looks like Red Oak. Setting pieces of raw or natural finished White Oak on top will show the contrast. If you can't tell by the coloration, range of color or deeper grain texture of Red Oak, the best way to tell is by the length of the medullary rays. Red Oak is short. White Oak is long. Here's a handy article outlining the differences.

http://www.wood-database.com/wood-articles/distinguishing-red-oak-from-white-oak/