Bees produce honey from nectar that they gather from different floral sources. The color and the taste of honey they produce hence is dependant upon the flower they visit. This is also what gives the honey its name, for example, Apple blossom honey is produced in hives that are typically place in or in close proximity to an apple orchard.
A common misconception amongst many is, "Pure honey never crystallizes". The truth is, all honey crystallizes at a certain temperature. So what to do when you have crystals forming in your honey? Set it on a warm sunny window or in a warm place or simply stick the bottle of honey in a warm water bath and leave it overnight. The important thing is that you do not want to heat that honey over 100F if you want the benefits of honey to remain. After 120F, the honey loses it priveledges of being called "raw".