What is the difference between glaical ice (Glacier) and Normal ice ?

The difference here lies in the air content. Ice cubes in the freezer compartment form simply by freezing, so that a lot of air is also trapped with the water . On the other hand, forms from snow that is pressed down over long period and refreezes again and again.If the the process is repeated often enough and more and more snow is added, then firm (containing just 50% of air) will form. This form of ice gradually increases in density and n the period of thousand years firm become the typically blue or greenish glistening glacial ice that has just 2% air content.