Ahh the silent stare. It can mean quite a few things depending on exactly how she looks .
Personaly I think its curiosity.

If so, then she may be trying to work out how she feels. In her mind she may think your a nice guy, but she is trying to find out how she feels in her heart.

I would give her some time before you do anything big. She has to work out something for herself, but you can help her draw a conclusion by making a few small moves every now and then.

Such as a smile (try practicing in the mirror, you dont wanna give her the wrong sort of grin ), making eye contact for a bit (not too long to make it weird, nor too short so that its only a glance) or light physical contact, such as when she passes you a pen take it so that one of your fingers lightly touches hers (it works on me, so it probaly works on her too).
Things like that should help.

If that is whats going on insider her head, then you may have a chance, but it could be thin ice, but Im sure you will do fine, try and see if she gives your friend the same look, since he may be in the same situation.
But I could also be wrong.

Also, I think that when they dont look away, it might be their way of getting your attention, possibly meaning that they want you to make some sort of move. Im not so sure on that one, perhaps one of the girls could clear that one up for us if they have an answer. It could be something they are not aware they are doing.

Either way - Good Luck

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