Should car antifreeze look like oil?

I got my car antifreeze flushed and filled less than a year ago. When I look at it it looks dark like oil and I feel it should be green. Two quick lube places say it is bad. I took it back to where I got the flush done and they say it is good for 50 below zero and nothing is wrong. Isn't there still something wrong with the color of antifreeze? This car is a 2000 Buick Century. What color should antifreeze look like and what is wrong with mine?