Why do some varieties of artisan honey crystallize into a solid thick white sugary paste inside the jar over time?

Crystallization is a natural hallmark trait of pure unheated raw honey. Honey is a highly supersaturated solution containing two primary natural plant sugars: glucose and fructose. Over time the glucose separates from the water content naturally locking into solid crystal shapes. Submerge the sealed jar in warm water at 45°C to liquefy it safely.