WHY IT BECOME HARD & THICK
Honey is a natural product which we consume. So, we can see some changes due to climatic change. Sometimes glucose will separate from honey in its own form. This crystallization of glucose may lead misunderstanding as duplicity of honey with sugar or jiggery. The reality is that honey contains glucose. This crystallized honey called comb and do not put into stove. It will melt easily in sunshine or hot water. We can keep and use it for long term, and it does not have any bad effect. But, heating this comb in a stove or heater will bring bad effect. Only climatic change will cause only behind this comb effect.
A common misconception is that granulated or crystallized honey is proof of adulteration with sugar water. The truth is honey is a supersaturated sugar solution and can granulate whether or not it has been adulterated, so crystallization is normal, especially in temperate climates. Furthermore, some honey from certain floral sources is especially prone to crystallization.