Appearance: Opaque, often veined.
Colour: blue, turquoise.
Properties: Empathetic, balances. Promoter of self-realisation, creative problem solving. Heals, protects, purifies, dispels negative energy. Unites earth and sky, male-female, provides healing for spirit. Strengthens meridians of body, subtle energy fields. Enhances physical/psychic immune systems. Alleviates pollution. Heals whole body, especially eyes.
Dimensions: Size and photo are a sample.
Disclosure: If you're worried about your health always see your doctor first. There are no guarantees with crystals, but they may enhance your life.