Affinity with the signs: Scorpio, Leo, Aries and Gemini.
For Native Americans it is a sacred stone used in celebration and in connection with "ancestral rituals". With a very strong Earth element it is good to connect and anchor your energy. Good for those who need to focus and become more present.
Approximate dimensions: Between 15mm to 20mm
The affinity of the stones with the signs just means that there is potentially more reverberation between them. But it shouldn't be the reason to look for another stone if it looks right to you, regardless of your sign.