The Natural black olives harvesting season begins in November and December. Varieties of Natural black olives : Manzanilla Natural black olives: Calibration from 140 to 400 pieces per kilogram. Picual Natural black olive: Calibration from 140 to 400 pieces per kilogram. Dolci Natural black olives : is known for its sweetness or mild flavor , Calibration from 120 to 300 pieces per kilogram. Shapes : Available in whole natural olives , pitted natural olives and sliced natural olives .