Mustard can come in several different colors, yellow, brown and black. Black Mustard is the more uncommon of the three. Mustard seeds are ground up and used in many condiments include you guessed it, Mustard. In India, Mustard Seeds are added to oil before cooking. When the seeds begin to crack, they add a mustard flavor into the oil. In Europe, Mustard Seeds are important for preserving and pickling.