These earrings are great. I purchased them for my girlfriend and she loves them - shows them off to everyone when she gets a chance. We're 22 years old and she has relatively small ears but I feel these would be adequate size for even average sized ears. That being said, they are a little small - but they aren't TOO small, 1mm more in diameter would be perfect for average sized ears.

Gem quality: despite being black diamonds, they did refract some light and you could see tiny light pinpoints projected from the facets onto surfaces when the diamonds are put under light. This effect is not very noticeable while being worn but this is as one should expect from black diamonds.
You can faintly make out some flaws on the interior of one of the diamond but you really have to look for them and could just be my imagination.

Overall: probably my girlfriend's favorite gift I have given her in terms of jewelry (on top of silver bracelets, rings, necklaces) I would get them for her again except that she already has an awesome pair as it is!