Good size for work on child or small woman as you can work all areas easily. Smaller size approximate 3x2" for smaller hands, very comfortable to hold. "Wood" element.
These are made for China's doctors, and are made in the traditional style that includes minor imperfections on the jade. Not damage, just part of Chinese medicine culture. The story is included in the information sheet. Each is slightly different.
Genuine and natural Chinese jade, the color may be slightly different as they are carved from the stone. You can see the variation of color in the photo with the "hand" that shows the approximate ratio of gua sha tool and hand.