There is only one Gemini constellation in the night sky. The name "Gemini" comes from the Latin word for "twins," and the constellation is depicted as two figures, Castor and Pollux, representing the twin brothers from Greek mythology.

It's possible you might be thinking of the two brightest stars in Gemini, which are called Castor and Pollux. These stars are not separate constellations, but rather the most prominent stars within the Gemini constellation.

Let me know if you have any other questions about the night sky!