Hardness: 7 Specific Gravity: 2.66 Species: Quartz, Opaque Chalcedony Treatment: Dyed Care: Avoid heat and harsh chemicals. Ultrasonic and steam cleaning are usually safe.
Black onyx is believed to be one of the most powerful protection stones. Its way of doing this is to absorb and transform negative energy. Because of this quality people find it helpful in relieving stress and for emotional stability. It's one of the first (root chakra) grounding stones; as such,it encourages connection to material goals and to determination in realizing them. In much crystal literature black onyx is strongly associated to Saturn, and it is said that this stone works most positively for those with a strong Saturn in their natal charts. Although this may include people born under the sign of Capricorn, it's not limited to them.
I mention the above because it's part of the lore about this stone; however, black onyx has another characteristic which can make it valuable to anyone. It has been said that in India it was commonly worn to cool the ardors of love. Thus it may be very helpful for people who can't let go of past relationships (sometimes even long after they're over.)
The same can be true of any belief which no longer serves one - and they can be as hard to let go of as past relationships. Onyx's value in such situations is that it can help to bring us into contact with our actual realities, and assist us in gradually releasing all that is not in harmony with our present lives.