Gemini stars are not a specific spectral type, so they don't have a single color or surface temperature. "Gemini" refers to the constellation Gemini, which contains many stars of different types.

To determine the color and surface temperature of a star in Gemini, you would need to know its spectral type.

Here's a general guide to color and surface temperature based on spectral type:

* O: Blue, 30,000-50,000 K

* B: Blue-white, 10,000-30,000 K

* A: White, 7,500-10,000 K

* F: Yellow-white, 6,000-7,500 K

* G: Yellow, 5,200-6,000 K

* K: Orange, 3,500-5,200 K

* M: Red, 2,400-3,500 K

For example, the brightest star in Gemini, Castor, is a binary star system with a spectral type of A1 and A2. This means that both stars in the system are white, with surface temperatures around 9,000 K.

To find the specific color and surface temperature of a star in Gemini, you would need to look up its spectral type in an astronomical catalog or database.