Does the color of the oil attest to its quality?

The color of olive oil is not indicative of its quality.

The color of the oil is influenced mainly by the time when the olives are harvested and the variety of olive. A green olive picked at the beginning of the harvest will yield an oil that is a darker shade of green, while a dark olive picked at the end of the harvest will yield a lighter green oil.

Incidentally, there is no such thing as green olives and black olives – they are the same olives at different maturity stages, just like tomatoes. For this reason, it’s important to buy olive oil from someone you trust rather than simply relying on its appearance, which can be misleading and confusing