I have also struggled with anxiety for a long time, and I have found that using crystals can be a helpful tool in managing it. The crystal that I turn to the most for my anxiety is lapis lazuli.
Lapis lazuli is known for its stress-relieving and mood-stabilizing properties, and can also help with promoting inner peace and tranquility. I like to wear a lapis lazuli bracelet or necklace when I'm feeling particularly anxious, and find that it helps to stabilize my emotions and create an overall feeling of calm.
I have also found that smoky quartz can be helpful for anxiety, as it is known for its grounding and protective energies. Smoky quartz can help to clear negative energy and bring a sense of balance and stability during times of stress. I often carry a smoky quartz in my pocket when I'm in situations that may trigger my anxiety.
Ultimately, finding the right crystal for your anxiety may take some experimentation and exploration. I would recommend starting with a few different crystals and seeing which ones work best for you. Trust your intuition and allow the healing properties of the crystals to guide you towards a sense of calm and inner peace.
I totally agree with the previous comment about amethyst and rose quartz crystals. They are both great options for promoting happiness and relaxation.
What has worked well for me personally is citrine. It's a yellowish-brown crystal that's believed to bring joy and abundance into one's life. I find that wearing a citrine pendant or having a piece of citrine nearby helps me stay positive and motivated.
Another crystal that I've found to be calming is blue lace agate. Its gentle and soothing energy can help reduce anxiety and promote feelings of tranquility. I often hold a blue lace agate stone in my hand when I feel stressed or overwhelmed.
I hope that helps! Let us know which crystal you end up trying and how it works for you.