Sterling silver black onyx dangle chain Black Onyx is widely recognised as one of the strongest protective crystals ever found. It will form a protective shield around your Aura, blocking off any negative energy or intention coming your way. Black Onyx will ground you and provide you with a sense of stability which will allow you to let go of any anxious or fearful thoughts you may be holding onto. It is also a great crystal to work with to magnify your intentions.