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Best known as a deep black stone, onyx also comes in colors like white, brown, green, pink and yellow. The stone often features stripes, which can be thin or thick, in red, brown, black, white or gold. Yellow onyx is often used as a construction material, but the ancient Roman and Aztec healers believed the stone had powerful properties. Astrologers believe stones like onyx have the power to affect the human body through a series of vibrations that radiate the body's seven chakras, or energy centers.

Physical Properties

A member of the quartz family, onyx -- including yellow onyx -- has a hardness of 7 on the Mohs scale. The scale rates gemstones from 1 to 10, with 10 being the hardest.

Healing Properties

Being a member of the quartz family, onyx is believed to have healing properties. Yellow onyx is said to help with healing wounds, regulating organ function and strengthening the back. Healers also use the stone to address ailments in the eyes and ears.

Solar Plexus Chakra

Yellow onyx is said to open the solar plexus chakra, or the third energy center. This chakra is associated with physical strength and emotional stability. You can place yellow onyx or other yellow stones on your solar plexus to open and gain control of your solar plexus chakra; once you attain this control, you can gain a sense of peace.

Other Properties

Yellow onyx is associated with seriousness and logic, and is said to help one who wears it know when to keep silent in certain situations. Physically, onyx can help sooth anxiety and depression and can boost emotional strength.