Which of these is pure honey?

I bought 2 different honey couple of months back, both looked same at that time. One on the left is from Vediko origins and on the left is Vindhya Valley. Now due to winters, temperature has dropped below 10 degree celsius (below 50 degrees Fahrenheit). Why is left one crystallized while other doesn't? Which of them is pure? Is there any way to know that at home?