Onyx, “scrying stone”
Reputed to be the eleventh, or Shoham stone in the breastplate of the High Priest inscribed with the tribal name of Gad. Onyx comes from the Latin and Greek words meaning “claw” or “fingernail” for its resemblance to the human nail, and is referred to by the Arabic term el jaza meaning “sadness.” Onyx is a stone of separation, and can be helpful in recognizing old habits or relationships that need to be re-evaluated or released, and brings the inner strength needed to let go. Onyx stimulate the Base Chakras, often leads to independence and spontaneous leadership, while grounding oneself.
Onyx honors Bean Sidhe, the Irish Fairy of Mourning, and Manat, the Arabian Goddess of Time, Destiny and Death. She is honored because time brings us all a transition, we call death, but in life she can bring a world filled with magic, wisdom and protection.
Onyx honors Cybele, the Roman Earth Mother and Goddess of Wild Animals. 
References:-
[Ahsian, pp.] Robert Simmons & Naisha Ahsian, The Book of Stones (Berkley, CA: North Atlantic Books, 2007).
[Eason, pp. ]Cassandra Eason, The New Crystal Bible (London: Carlton Books Ltd., 2010).
[Fernie, pp.] William T. Fernie, The Occult and Curative Powers of Precious Stones (Blauvelt, NY: Rudolph Steiner Publications, 1973).
[Gienger, pp.] Michael Gienger, Healing Crystals (Scotland: Earthdancer Books, 2009).
[Hall, pp.] Judy Hall, The Crystal Bible (Cincinnati, OH: Walking Stick Press, 2003).
[Hall 2, pp.]Judy Hall, The Crystal Bible 2 (Cincinnati, OH: Walking Stick Press, 2009).
[Kunz, pp.] George Frederick Kunz, The Curious Lore of Precious Stones (New York: Dover Publications, 1971).
[Megemont, pp.] Florence Megemont, The Metaphysical Book of Gems and Crystals (Rochester, VT: Healing Arts Press, 2008).
[Melody, pp.] Melody, Love Is In The Earth (Wheat Ridge, CO: Earth-Love Publishing House, 1995).
[Raphaell, pp.] Katrina Raphaell, Crystal Enlightenment (Santa Fe, NM: Aurora Press, 1985)
[Simmons, pp.] Robert Simmons & Naisha Ahsian, The Book of Stones (Berkley, CA: North Atlantic Books, 2007).