Russet apple

Russeting on apples is a particular type of skin, slightly rough, usually with a greenish-brown to yellowish-brown colour.

Many apple cultivars have some natural russeting, but some are almost entirely covered in it, notably the Egremont Russet. Russet apples often exhibit a scent and flavour reminiscent of nuts, and are often very sweet. Despite this, modern apple breeders rarely accept russeting in new apple cultivars. The amount of russeting can be affected by various factors including, weather, disease or pest damage and agrochemical applications (e.g., insecticides, fungicides and growth regulators).

Russet apples also go under the name "rusticoat", "russeting" and "leathercoat". The last name was known in Shakespeare's time; for instance, in Henry IV, part 2, Davy says to Bardolph, "there's a dish of leathercoats for you".

...
Wikipedia