How do you identify a virgin by looking at her vagina?

There is no way of identifying whether or not a woman is a virgin by simply looking at her vagina. The hymen is deep within the vaginal canal, therefore you cannot see it and even if you could, you wouldn't be able to tell for sure if the girl was a virgin by looking at her hymen. It's not a piece of skin that breaks once you've had intercourse, it's just another smaller section of the canal that has to be stretched to accommodate the penis. However, sometimes activities earlier in life can stretch the hymen before sexual intercourse like vigorous exercise, bicycling, and horseback riding. If you're unsure whether your partner is a virgin, you'll have better luck actually asking her than looking at her lady parts.