I have worn obsidian & have also shielded by picturing a white egg shaped light over my entire body as well as saying with intent that I am with love and protected.
If you have been sludged by negative type energy either purposely or accidentally you can have a baking soda sea salt bath by adding 1/2 lb of each to your bath water (not too hot) that will remove the negative energy and cleanse your aura! You can also go for a swim in the ocean it does the same cleansing!
All of these work for me ❤️