Looking for answers
Good job remembering the tourmaline while out shopping. I'm glad you are noticing an improvement. And it's funny you mentioned Costco. Once in a while on weekends I get out of my weekly routine and forget my stones when running errands. And when that happens I have a real tough time at Costco. I don't know what it is about that place as I really like the store but get a lot of anxiety.
In my experience only about 1 out of 10 stones create a buzzing or electrical feeling (or in your case heat). That doesn't mean that the other ones aren't working. It just means the one that vibrates is at a higher vibration and may be a good stone for you. As humans when you are happiest you are at a high energy vibration. And when down and depressed you are at a low vibration. I have read that as empaths we have a higher vibration than others to start and can get our vibration a lot higher. When you learn to raise your vibration you will not only feel better but will bring healing and happiness to those around you.
I think the stones that have high vibrations and buzz in your hands can be useful to raise your vibration. But don't be surprised if they also make you feel dizzy or uncomfortable. That is your body adjusting to it. In that case, just hold the vibrating stone for a short amount of time each day and increase over time.
You will notice that some of the stones that work the best for you don't really feel like anything. My black tourmaline, black onyx, and black obsidian just feel like cold stones to me. They have never radiated or buzzed in my hand. But they work their magic and keep negative energy away from me each day. And I am very grateful for that.
The protection stones go through a lot for us. Some block negative while others absorb it to keep it off of you. So they do need some care. I like to set mine out in sunlight for the day every 2-3 days. But I also at times will let them soak in salt water for a day to clean and reinvigorate them.
I have a quick story on the practical use of stones. Rose quartz is known to bring calm and love and is supposedly especially effective for females. Every once in a while my wife gets grumpy or stressed and basically is well on her way to having a bad day. And I will covertly put a rose quartz on her nightstand or sneak one in her purse or on her desk. And while it doesn’t have an instant impact, it does calm her down and brighten her day. And just the other day I was at my doctor's office and she had a large rose quartz sitting on her desk. Others in this forum have put Rose quartz around their office to try to create more peace and harmony. Long story short, there are lots of stones and crystals that do some cool things. But for an empath struggling with anxiety and overload, protection stones are the best place to start.