Some important essential oil guidelines to remember: Essential oils should be diluted in a carrier oil to a maximum of 5% (see these 5 Face Oils For Naturally Clear, Flawless Skin and The Best Face Oils By Skin Type). So since 1 ml is 20 drops, for every 1 ml of carrier oil, you would add 1 drop of EO.
The San Francisco Peaks are composed of six peaks, including the four highest in Arizona: Humphreys Peak, 12,637 feet (3,851 m), Agassiz Peak, 12,356 feet (3,766 m), Fremont Peak, 11,969 feet (3,648 m), Aubineau Peak, 11,838 feet (3,608 m), Rees Peak, 11,474 feet (3,497 m), and Doyle Peak, 11,460 feet (3,493 m).
Distance from Phoenix: 144 miles north; two-hour drive. Why it made our list: Flagstaff is home to Humphreys Peak, the highest point in AZ and one of the few places to ski or snowboard in the state. Yes, it snows in Arizona. The High Country gets about 110-inches of the white stuff each year.