Colors in the ice

While skating, I noticed that the tracks in the ice glowed in intense colors in sunlight. Upon closer inspection, I saw that it was the cracks in the ice that lit up in different colors depending on the slope. They are about the thickness of soap bubbles and, just like these, create colored reflections. This effect is caused by the superposition (interference) of the light waves reflected on the front and back of the crack. Depending on the thickness and inclination of the crack, certain colors are erased and others are reinforced. The image section of the macro photos is about 2 cm. The colors are also easy to see with the naked eye.