What Am I?

I am a stone that embodies the image of beauty. My deep hue creates a feeling of serenity and balance. I inspire you to express positive energy that will protect me as I in turn promise to protect you. While blue is my main hue, many other brilliant colors can be identified as my stone. Even though I am one of natures most durable gems, I shall be respected and handled with love and care. As a result, my body will shine for generations. If you were born in the month of September, then I am yours.