Ruby is the representative mineral of Sun on earth. Chemically speaking it is a crystal of Aluminum oxide which is represented by the chemical formula Al2O3. Aluminum oxide is also known as corundum and physically is a very hard crystal second only to a diamond in hardness. Corundum is white in color but appears red due to some impurities caused by chromium salts. A single crystal of red corundum may exhibit different shades of red due to varying amounts of other salts. Rubies may therefore vary in color from pinkish to violet/purplish red in color. In strong light they appear brighter. Sun is the king and the father of the solar system and represents the ruling class as also the people with authority and power. Like Janma and Chandra Lagna, Sun too is considered a Lagna in itself. Sun represents self, ego, father, body, skeletal system, bones and general health. If Sun becomes the lord of Lagna, fifth or ninth house, he becomes very helpful and in such cases one can wear a ruby without a second thought. In other cases, a ruby should be worn keeping in mind the strength of Sun in the birth chart and whether or not his Maha Dasha is running.