Walter's comment led me to do a little research.

The Hass avocado /ˈhæs/, sometimes marketed as the Haas avocado /ˈhɑːs/, is a cultivar of avocado with dark green-colored, bumpy skin. It was first grown and sold by Southern California mail carrier and amateur horticulturist Rudolph Hass, who also gave it his name.

The Hass avocado is a large-sized fruit[4] weighing 200-300 grams. When ripe the skin becomes a dark purplish-black and yields to gentle pressure.[5] When ready to serve, it becomes white-green in the middle part of the inner fruit. Wikipedia