Jaggary, or gur, is basically boiled sugar cane juice. The longer it is boiled the more water evaporates and the final product is drier and harder. Jaggary is a totally different product to white sugar, even thought they are both made from sugar cane. For example, sugarcane juice is found to have reduced the number of teeth cavities, whilst refined white sugar is known to increase them.
Jaggary is heavy, moist and warm, whilst white sugar is light, dry and cold. Sugarcane jouice is moist and cool just to confuse things! White sugar is recommended as an antidote to make some hot medicines more tolerable for Pitta, but not as a regular food.
Jaggary balances Vata, but is too heavy and sweet for Kapha and too warm for Pitta to enjoy regularly. It is a very important source of nutrients and can be eaten daily by Vata. It is useful in cases like convalesence, pregnancy and post natal care. It has specific action on the lungs and is a very good blood builder. It is high in iron, and can be eaten daily with black sesame seeds for Vata type anemia. Jaggary also has the advantage of being sattvic, unlike white sugar (rajasic) or treacle (tamasic).
Since it naturally contains potassium and sodium jaggary doesn't cause a blood sugar spike like refined sugar does. Jaggary may be tolerated by diabetics a little better than white sugar, but raw honey is still best in this case. This mineral salt content also makes it excellent for rehydration or blood loss.
Jaggary is most typically used in India food for making sweets with sesame, coconut or milk. But Gujarati cuisine is famous for it's unique sweetness, and jaggary is used in dahl and vegetable dishes. A typical Punjabi meal is mustard greens with corn flour flat bread and a chunk of jaggary-delicious and really fun to eat!
If it looks light and dry it probably is, so most 'raw' sugar and 'brown' sugar likely shares more qualities with white sugar than jaggary. Find the most moist and gooey and dark sugar you can. In my experience gooey dark sugar made from coconut, date or palm has similiar qualities to that made from sugarcane, and may be more available.
It isn't as sweet as white sugar, and does affect the outcome of various baked goods, but I love it so much I use it in baking anyway. To use it in cooking you can dissolve it with a dash of warm water and use in place of syrups like honey (which shouldn't be cooked) and golden syrup (which is highly refined). This syrup is also delicious on pancakes. Dryer jaggary can be grated, and then blended to make a powder which can be used in place a regular sugar for a darker, heavier, less sweet result. Jaggary chunks can be easily dissolved in tea or porridge.