Zodiac: Virgo, Capricorn, Pisces, Libra
Chakras: heart, solar plexus
Properties: Named after Dutch mineralogist Hendrik von Prehn
Mental: Helps with alertness. Assists sorting thoughts, releasing chatter of the mind.
Emotional: Soothes feelings of unrest during major change. Helps see the benefits for self in change.
Spiritual: Teaches of the impermanence of all things. Useful for meditations on cycles of creation and destruction and the temporary nature of life.