The star signs or the zodiac signs which are there given by the motion of the stars and the planets and each star signs characteristic are determined by the fact that each has an element which determines the characteristics of an individual. Now there are various factors that you need to consider when you consider the compatibility.  

There is something called as the perfect compatibility and then there is the almost perfect compatibility and then in a lot of cases it is the opposites that attract each other. To know whether you are compatible or not always make sure that you have the best knowledge about each and every characteristics of the star signs as well as there are other factors like the male or female which lend its own color to the argument

The Gemini start sign the elements is air, and the ruling planet is mercury and the symbol of the Gemini is the twins. The stone for Gemini is the Aquamarine. The people who are Gemini are always moving and the reason may be because of the fact that these people are born under the effect of Mercury. Now mercury was the messenger of the gods and always going from place to place to deliver the message. That also means that Gemini have seen the world and would always be very curious and very much smart some call them street smart.

The compatible factor with Gemini are the Libra and the Aquarius and the next best ones are the Aries and the Leo.  

If we talk about exact opposites to the point that opposites attract each other then Scorpio are the ones that are best suited for Gemini. Never go with the Sagittarius as they are not at all suited for you.

The reason that an astrological sign that are compatible with Gemini that is the Aquarius as well as the Libra is that these two also belong to same element air and that can be big factors. The general rule that is there is that air like the air but then the earth signs match well with water and the water signs match well with the earth signs.

Are Gemini and Libra compatible and the answer is yes they are compatible simply because of the fact that they both are air signs. Same is the case with the Gemini Aquarius compatible. They are compatible because of the fact that they have the same star elements that is the air. Always read all the characteristics of each to make sure that you understand the true compatibility and also then you can go for the Chinese start sign compatibility if you want some more confirmation.