"Why does Honey Crystallize?" - Understanding the science behind it!

We often store Honey in cool and dark places (as suggested). However, over time we notice the Honey tends to crystallize and turn into a semi-solid state.
Why does this happen?
What does it tell us about the quality of the Honey?
How do we bring it back to its liquid state naturally? 
And most important question of all - Is it safe to consume?
Let's take a look at the science behind it that answers all your questions. 

Why does this happen?
Natural Honey is a supersaturated solution, meaning that it contains more sugar than would normally dissolve in water at room temperature. The two main natural forms of sugar being - glucose and fructose. 
When honey is in its liquid form, the sugars are dissolved in water and can move around freely. However, as the water content of honey decreases, the sugars become more concentrated and begin to bond together. Eventually, the glucose and fructose molecules form crystals, which grow and spread throughout the honey.

Several factors can influence how quickly honey crystallizes.
These include:
Temperature: Honey crystallizes more quickly at cooler temperatures. Ideally, honey should be stored at room temperature (around 70°F/21°C) to prevent crystallization.
If honey is stored in a colder environment, such as in the refrigerator, it may crystallize more quickly.
Type of honey: Some types of honey are more likely to crystallize than others. For example, honey that is high in glucose (such as Multifloral Honey) tends to crystallize faster than honey that is high in fructose (such as Jamun Honey).

What does it tell us about the quality of the Honey?
Contrary to popular belief, crystallized honey does not mean that the honey is fake or of low quality. In fact, crystallization at room temperature is an indication that it is 100% natural.

How do we bring it back to its liquid state naturally? 
Warm water bath: Place the jar of crystallized honey in a bowl of warm water (not boiling) and let it sit for a few minutes until it becomes more liquid. Stir the honey occasionally during this process. Be careful not to overheat the honey, as high temperatures can damage the beneficial enzymes and nutrients in the honey.
Place in sunlight. (Ensure the cap is tightly shut to avoid ants getting into the good honey) 

Is it safe to consume honey in the crystallized state and in the restored liquid form?
Yes, crystallized honey is still safe to eat! In fact, some people prefer the texture and flavor of crystallized honey over liquid honey. When restored to its natural liquid state, it is 100% safe to consume and doesn't change the quality or taste of the Honey.