Fire dragons can consume types of rocks, depending on the rock’s chemistry it can change the chemical balance of the dragon’s fire as well as the color. Fire dragons have a high internal core temperature they need to maintain in order to stay healthy. These dragons are able to heat up their scales to dangerous temperatures. They are known for their hot tempers. 

Pyrokinesis - Manipulate flames, fire, and heat in the surrounding area. Also have an immunity to burning and have a thin but strong and invisible coating of wax/chemicals on their scales to prevent burning as well as provide insulation to keep themselves warm. 

Pyrotechnics - By heating up certain chemicals in their body, they can create a combustible combination and produce fireworks or a bright/flashy display of color from their body. 

Color-Manipulation - Changing the color of their flames through chemicals produced in their body. Example: Red -> Blue flames when feeling intense emotions that heat up their core temperature to such a degree that their fire becomes hotter.