The key differences between an olive tree and a black olive tree are:
Size and Appearance: Olive trees can grow up to 40 feet in height and have small, gray-green leaves with gnarled trunks. In contrast, black olive trees, also known as Shady Lady or Bucida Buceras, are smaller (about 20 feet tall and wide), with more rounded, glossy, dark green leaves.
Growing Conditions: Olive trees prefer full sun and are drought-tolerant. Black olive trees, however, are more shade-tolerant and are often used indoors.
Fruit: Olive trees produce olives, used in cooking and cosmetics. Black olive trees produce small, inedible black berries, serving only ornamental purposes.
For more detailed information, you can read the full article on the La Résidence blog here.