Clone copies the exact copy of the original (same address.id) and the dup copy is a new record (address.id = nil). Any changes you will made in the clone copy will be changed the original object, but any changes to the dup copy attributes will remain isolated.

for example:

pry> original = Profile.find(5)

  Profile Load (0.7ms)  SELECT  "profiles".* FROM "profiles" WHERE "profiles"."id" = ? LIMIT 1  [["id", 5]]

#<Profile id: 3, first_name: "david", last_name: "backham", email: nil, created_at: "2015-01-10 17:37:00", updated_at: "2015-01-10 17:37:00">

pry> clone_copy = original.clone
#<Profile id: 3, first_name: "david", last_name: "backham", email: nil, created_at: "2015-01-10 17:37:00", updated_at: "2015-01-10 17:37:00">

pry> dup_copy = original.dup
#<Profile id: nil, first_name: "david", last_name: "backham", email: nil, created_at: nil, updated_at: nil>

Note: With CLONE you can copy any singleton methods of an object but DUP does not support this.