Short answer: This is old growth North American White Oak with Woca Oil Rub Finish.

Longer answer: This is an old floor in San Francisco that is at the end of its life. It is the SF traditional 5/16 X 2" top nailed Oak that has been popular for decades. It handles our humidity changes - rain forest in the winter and desert in the summer. It was originally 5/16" thick but has been sanded many times. The owner wanted to preserve what was left. She chose a Woca oil rub finish. In theory it will never be sanded again. But it has to be properly maintained. It requires regular mopping with a specific soap that contains fats. It will require refresher coats. Do your home work on the maintenance before you have oil rub finishes applied. I strongly recommend against having oil rub finishes in houses that also contain urethane finished floors. The maintenance is totally different and if the wrong cleaner is used it can damage the hardwood.

We followed Woca instructions for sanding and coating except we applied 2 coats of the master oil and one coat of their maintenance paste (probably one coat more than really needed). The colors of this old growth Oak came alive with the Woca. Newer woods will not have this same patina or tight grain.

A beautiful old floor!