This a single 30mm d6 die that part of the Gemini line. It's perhaps the most unusual member of the Gemini line in that you see a third color pop through. It is yellow with blue and the third color is green (yellow and blue make green after all) with white pips. Thirty millimeters is a little larger than 1".
The particular die in the photo are just one of the dice that I have ordered. Thus, the actual die that you receive will be the same colors but may have slightly different markings. No two dice will be exactly identical.