The black ones are have softer flesh that separates from the pit more easily.
You may also see Cerignola olives that are bright red. These have a food colorant added for a festive effect. The colorant most often used in Italy is known as E127 or Erythrosine.
You can buy the prepared olives in a oil, or in a brine.
The olive is also sometimes used for oil; it has an oil content of 16 to 19%.
The olives are better for eating out of hand than for cooking with.
Literature & Lore
Native to Apulia.