All 78 zodiac combinations can be successful. In this world, we can find an example of each pair end in marriage or end in divorce. With that said, it's best to know how the blueprint of these relationships works rather than considering compatibility.
Gemini and Capricorn are going to be a very odd pair. Gemini is constantly on the go with thought. Some consider Gemini to be the genius zodiac. Capricorn plans, they hibernate, and really mull over their thoughts. Gemini is a mutable sign, Capricorn is a cardinal sign. Gemini is fairly agreeable, sometimes even a space cadet. Capricorn is ambitious and will strive to meet their family's needs. Gemini will look to Capricorn to be practical, and Capricorn will look to Gemini for expertise. The two can connect based on their brains. Both need to be okay that they operate at different speeds. Conflict arises because Gemini is swift and full of nerves, while Capricorn is steady. Both have great senses of humor.