Vivianite:  Avoid exposure to direct sunlight as it will bleach the color from the crystal.  Each piece measures approximately: 3" -to- 5.5" x 0.5" -to- 0.75", 8g -to- 12g Photo is representative of the color and quality of the stones. Each piece is naturally unique and sold individually. Rock Mama works intuitively to select the one intended for you.