Raw honey is the concentrated nectar of flowers that comes straight from the extractor; it is the only unheated, pure, unpasteurized, unprocessed honey.
An alkaline-forming food, this type of honey contains ingredients similar to those found in fruits, which become alkaline in the digestive system. It doesn't ferment in the stomach and it can be used to counteract acid indigestion. When mixed with ginger and lemon juices, it also relieves nausea and supplies energy. Raw honey is the healthiest choice amongst the various forms of honey as it has the most nutritional value and contains amylase, an enzyme concentrated in flower pollen which helps predigest starchy foods like breads.
Honey Pollen
Most honeys found in the supermarket are not raw honey but "commercial" honey, which has been heated and filtered so that it looks cleaner and smoother, more appealing on the shelf, and easier to handle and package. When honey is heated, its delicate aromas, yeast and enzymes which are responsible for activating vitamins and minerals in the body system are partially destroyed. Hence, such honey is not as nutritious as raw honey.
Characterised by fine textured crystals, raw honey looks milkier and contains particles and flecks made of bee pollen, propolis, honeycomb bits, and broken bee wing fragments. Raw and unfiltered honey is relatively low in moisture content (14% to 18%) and has a high antioxidant level. It will usually granulate and crystallize to a margarine-like consistency after a month or two. Many people prefer to spread it on bread and waffles, dissolve it in hot coffee or tea, or use it for cooking and baking.
You may also find raw honey that are unprocessed but slightly warmed to retard granulation for a short period of time and allow light straining and packing into containers for sale. In this case, the honey will not be considered 100% "raw" because it has been heated slightly and therefore rightfully should not be labeled as such by the supplier. There's a very simple way to tell if honey has been heated or not: hold it up to the light. If the honey is clear, then it's been heated.
Source: http://www.benefits-of-honey.com/raw-honey.html