When comparing appearances of the two types of olives, we can summarize as follows:

• Color: Black olives range from deep purple to black, while Kalamata olives are typically deep purple.
• Shape: Black olives are round to oval, while Kalamata olives have an almond shape.
• Surface: Black olives have a smooth surface, whereas Kalamata olives exhibit a wrinkly skin.
• Texture: Black olives have a soft and slightly chewy texture, while Kalamata olives are firmer and meatier.