My husband and I are purchasing a sectional made out of eucalyptus. It is stained a dark color - close to espresso. I would like to seal/treat it. What could I use?

I know and teak oil - would that be the best thing to use? It will sit on a concrete patio and I'm afraid even in sunny California where it never rains in the summer this will prove too moist for it. Should I look into something like Minwax?

Thank you so much for any advice!