Obsidian, Black
Obsidian is a very protective stone, and is excellent for removing negativity. It is also excellent protection against psychic attacks. In particular obsidian protects the gentle from abuse. It is a very grounding stone, and very healing. Obsidian is also an excellent manifestation stone. Physically it benefits the stomach, intestines, muscle tissue, and can rid one of bacterial or viral infections. It sharpens and focuses internal and external vision, and helps get in touch with buried issues before they explode. Obsidian is related to the root chakra.
Obsidian, Rainbow (Sheen Obsidian)
Rainbow Obsidian (Sheen Obsidian) is called a "stone of pleasure" because one of its most notable attributes metaphysically is bringing pleasure, enjoyment and joy to one's life. It also brings love and light to one and can bring out the Spiritual. Rainbow Obsidian is used psychically to enhance clairvoyance and is an excellent scrying stone, especially in the areas of love, relationships and self-development. It is also a very protective stone, and is especially effective in protection rituals and amulets, where it works by grounding out negativity to let light in. Thus, it is also a very grounding and centering stone. Rainbow Obsidian is primarily associated with the root chakra.
Obsidian, Snowflake (Snowflake Obsidian, Gray Snowflake Obsidian, White Snowflake Obsidian)
Snowflake obsidian has the property of bringing things to the surface. The things brought to the surface could be positive or negative, love, anger, secrets; but with snowflake obsidian, these things are brought to the surface more gently that they might be otherwise. Snowflake obsidian can provide balance during times of change. It aids in seeing patterns in life and recreating them in a more beneficial way. It is a stone of serenity and purity, and can shield against negativity. It is associated with the root chakra and is beneficial for the veins, skeleton, and smooth skin. Snowflake obsidian gives protection from physical and emotional harm.
Okenite
Okenite is often called a "warm and fuzzy" stone because it brings feelings of the "warm fuzzies", feelings of comfort and belonging. Emotionally okenite encourages forgiveness of self and others, and lessening of denial. It can bring truth with self and others and ease the harshness of that truth. It also helps break bad habits of all kinds. In the psychic realm, okenite is an excellent helper stone for channeling angels and other benign beings. Okenite is a purifying stone. Physically okenite is helpful for blood diseases and problems, lowering fever, stomach problems, and slowing aging. Okenite is associated primarily with the crown chakra but can align and purify the energy of all chakras.
Onyx
Onyx is associated primarily with the root chakra. It assists with challenges in life, especially those caused by a drain of energy. It prevents the draining away of personal energy and can be used for protection from such. It also helps with grounding and controlling or eliminating excess or unwanted energies. It has been used for wound healing, childbirth and to increase stamina and self-control. Black onyx and red onyx are associated with the base (root, first) chakra. White onyx is associated with linking the base and crown chakras to have balanced energy throughout the chakra system. Other colors are associated with the related chakra by colors.
Opal
Opal is a stone of inspiration which enhances imagination and creativity. It helps one release inhibitions and enhances memory. Opal is also a very spiritual stone, and can help one be "invisible" in situations where they don't care to be noticed. It is said to be a stone for love, as well. Opal brings happy dreams. It also eases the process of change. Physically, opal is said to be helpful for eyesight and Parkinson's disease.
Opal, Blue Peruvian (Blue Andean Opal)
Blue Peruvian (Andean) Opal is mystically known as a stone of courage and ingenuity. It is said to improve self-esteem and self-love. It is also said to be an aid to creativity and communication of all types. It is reputed to help one find a confidant. Peruvian blue opal is also said to help with stress reduction, fatigue, and weight loss. Crytal healing lore reputes that Peruvian (Andean) blue opal is physically healing for fatigue, chronic fatigue syndrome, metabolic balance issues, iron absorption, dizziness, and brain disorders. Blue Peruvian opal is associated primarily with the throat chakra.
Opal, Mexican Fire 
Mexican Fire Opal shares the properties of all opals and also has its own personality and energies. Mexican fire opal brings vitality and a creative energy to endeavors. It also had energies of ability to handle change well and comfortably. Mexican Fire Opal is also a stone of sensuality and sexuality, enhancing those energies. It is often used in clairaudience as well. Mexican Fire Opal is said to help with headache pain. Yellow Mexican Fire Opals are associated more with the solar plexus chakra, Orange with the sacral chakra, and Red with the root chakra, though all colors are also associated with the lower chakras in general. Fire Opals from other localities have similar energies.
Opal, Mexican Water
Mexican Water Opal also shares properties of all opals in addition to its personal energies. Mexican Water Opal has a Yin, receptive energy. It brings a strong motherly energy to activities to support beginnings and learning, especially. It is used for clairvoyance and other intuitive awareness. Mexican Water Opal is reputed to help with feminine health problems, lungs, and throat illness. It is commonly associated with the higher chakras. Water Opals from other places have similar energies.
Opal, Pink Peruvian (Pink Andean Opal) 
Pink Peruvian Opal is a stone of love and gentleness. It brings energies of gentle love and kindness to both romantic relationships and relationships of other kinds. As with other opals, it also brings inspiration, imagination and creativity. It can help release inhibitions and brings happy dreams. It also eases the process of change. Physically, pink Peruvian opal is helpful for eyesight, heart disease and injury, Parkinson's disease, lungs, and spleen. Pink Peruvian opal is associated primarily with the heart chakra.