Very good catch on the difference between the atmosphere on Mars and the atmosphere on Earth.
It's always had to tell a not obvious mineral from a photo. I was looking for cleavage, like the quarter circle bottom, left corner.
I don't see any translucence to it. I did notice all the rocks around it also have the teal green tint to them. So is it something they did to the image?
I did notice the green pebbles around the rock which is curious. Don't know why NASA would mess with the color. I thought maybe from the impact.