About Opal – History and Introduction
Opal Gemological Properties
Opal – Similar Materials
Opal – Metaphysical Powers
Opal Jewelry Ideas
Opal is the most colorful of gems. Its splendid play of color is unsurpassed, and fine examples can even be more valuable than Diamond. The play of color consists of iridescent color flashes that change with the angle at which the stone is viewed. This phenomenon is often called opalescence. The play of color may consist of large, individual flashes of color (known as schillers), or may be of tiny, dense flashes. The intensity and distribution of the color flashes is a determining factor in the value of an Opal.
About Opal – History and Introduction
Opals displaying play of color are known as Precious Opals, and opals lacking play of color are known as Common Opals. Gems can be cut from both the precious and common forms, but Precious Opal is the primary gem form of this stone. There are many varieties of both precious and common Opals. The most desired and beautiful form of opal is Black Opal, which is opal with a dark blue, dark green, or black background with a strong play of color. Next in importance is White Opal, which is Opal with a light colored body color (white, yellow, cream, etc.) with strong play of color. Also important is Fire Opal, or Mexican Fire Opal, which is a transparent to translucent deep-orange red form of Common Opal. Fire Opal can also display play of color, and this is a rarity called Precious Fire Opal.
Many precious Opals, besides being classified as either black or white Opals, are further classified based on the distribution and habit of their play of color. Some of these names have older sources, while some are recently coined trade names.
Opal doublets, often used in jewelry, are thin slices of precious opal glued onto a base material. Such gems are considerably cheaper than solid opals, yet provide the same play of color. Opal doublets are sometimes coated with a thin layer or dome of clear Quartz to make them more resistant to scratches (since Opal is a relatively soft gem). These are sometimes called Opal triplets.
A condition called crazing affects certain Opals, causing them to form internal cracks. Crazing is an interesting phenomenon, as it lacks consistency and is sometimes unpredictable. Although it can occur at random, its often takes place when an Opal removed from damp conditions is allowed to dry too quickly, or when an Opal is exposed to sudden intense light. Crazing may also take place when an Opal is subject to vibration, as during the cutting and polishing of a gemstone. The severity of the crazing and the time it takes to “craze” varies among gemstone. The origin is often a determining factor to its resistance to crazing, as some localities are less prone to crazing than others. A gradual drying process over months or even years can in some cases effectively stabilize the stone and allow it to be cut and polished with a substantially reduced risk of crazing.
Australia is the largest producer of Opal. Other important deposits are in Ethiopia, Sudan, Hungary, Honduras, Brazil, Mexico, Canada, and the United States (Nevada, Oregon, California, Idaho).
Opals are occasionally treated with soaking in waxes or synthetic lubricants to enhance luster and stability. Gemstone rough Opal is usually sold in buckets of water to enhance the play of color effect which is stronger when an Opal is wet.
Opal Gemological Properties
Chemical Formula: SiO2 · nH2O
Color: White, Colorless, Blue, Red, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Black, Banded, Multicolored
Hardness: 5.5 – 6.5
Crystal System: Amorphous
Refractive Index: 1.37 – 1.47
SG: 1.98 – 2.25
Transparency: Transparent to translucent
Double Refraction: None
Luster: Vitreous, pearly, waxy
Mineral Class: Opal
Opal – Similar Materials
The play of color exhibited in Opal is distinctive, and no natural gemstones can duplicate Precious Opal. Fire Opal may be similar to Topaz, Citrine, and Carnelian.
Opal has an abundance of varieties. Some, such as Black Opal and Fire Opal, are universally accepted, while many others are either occasionally used or made up by dealers. The names below are names heard or seen being used by many dealers. There are many other names besides for this list, but they are rarely used and some are made up by dealers and not accepted.
Andamooka Opal – Opal from Andamooka, South Australia.
Banded Opal – Form of Opal with color bands.
Black Opal – Precious Opal with a black, dark blue, dark green, dark gray or similar darkly colored background or base color. Black Opal is the most valuable form of Opal.
Boulder Opal – Precious Opal from Queensland, Australia, found in the cracks of, or as coatings on, ironstone or sandstone boulders.
Cherry Opal – Orange-red to bright red variety of Mexican Fire Opal.
Chrysopal – Opal similar to Prase Opal, but with a golden-green color.
Claro Opal – Transparent Opal from Mexico with an intense red, green, blue, and yellow play of color.
Common Opal – Any Opal without play of color.
Contra Luz Opal – Opal where the play of color is visible only when a light source is behind the stone.
Fire Opal – Yellow-orange to red Opal.
Flash Opal – Opal with large schillers that abruptly appear and disappear as the stone is rotated.
Gilson Opal – Synthetically produced Opal created using the Gilson process.
Harlequin Opal – Opal in which the play of color is arranged in a consistent harlequin, diamond-shaped, or rectangular-shaped pattern that is very vivid. Harlequin Opal is one of the rarest and most prized forms of Opal.
Honey Opal – Transparent to translucent Opal with an orange to orange-brown, honey-colored background. It may or may not display play of color.
Hungarian Opal – Describes Opal from the old sources in Hungary (as well as other places in Europe such as the Czech Republic). This term has become corrupted and is sometimes used to describe White Opal from other locations as well.
Hyalite – Colorless, light yellow, or blue transparent variety of Opal, lacking play of color.
Jelly Opal – A transparent Precious Opal with a gelatinous appearance and a bluish sheen. Jelly Opal may also refer to a colorless, transparent Common Opal.
Lemon Opal – Opal with a lemon-yellow color.
Lightning Ridge Opal – Opal from Lightning Ridge (New South Wales), Australia. Although different forms of Opal are found at Lightning Ridge, this term often represents the high quality Black Opal found there.
Mexican Fire Opal – Form of transparent Opal from Mexico, usually with an orange or red colors. Mexican Fire Opal usually refers to the form without play of color. If it exhibits a play of color, it is known as Precious Fire Opal.
Moss Opal – Opal containing inclusions resembling moss.
Nevada Opal – Opal from the Virgin Valley (Humboldt Co.), Nevada.
Onyx Opal – Opal resembling banded Onyx.
Opal Jasper – Form of Brecciated Jasper in which the cementing material is Opal.
Opal Matrix – Thin layer of Opal on host rock (matrix).
Pinfire Opal – Opal with very small, pinhead-size color flashes.
Precious Fire Opal – Yellow-orange to red Opal (Fire Opal) with play of color.
Precious Opal – Any Opal with a play of color.
Slocum Stone – A synthetically grown Opal. Also called Slocum Opal.
Virgin Valley Opal – Opal from the Virgin Valley (Humboldt Co.), Nevada.
Wax Opal – Yellow to brown Opal with a waxy luster.
White Cliffs Opal – Opal from the White Cliffs, New South Wales, Australia.
White Opal – Precious Opal with a light colored body color, such as white, yellow, and beige. (Differentiated from Black Opal which has a dark background color.
Yowah Nut – Small, rounded form of Opal from Yowah (Queensland), Australia in a nodule embedded in ironstone. Closely related to Boulder Opal, it occurs most often as walnut-sized ironstone nodules containing pockets, veins, or sprinklings of vivid Precious Opal.
Opal – Metaphysical Powers
Opal is a stone of inspiration which enhances imagination and creativity. It can bring inspiration to projects and to life and Spirit. Its own spirit is at times like that of a child spontaneously playing, dashing color where ever it pleases. Carrying this imaginative spontaneity into the realm of you life can bring strong creativity.
Opal has a larger proportion of water in it than most stones and is considered a water stone. This can help ease the effort of handling change in life. Like water rolls over and past rocks and roots in its way, the energy of opal can help continue on your path regardless of obstacles. During times of transformation, this is an invaluable energy to work with and hold close to your heart.
Mentally, opal is said to enhance memory. It is also used to decrease confusion.
In the psychic or spiritual realm opal is used for high spiritual crystal energy vibrations. It is said to be able to help one be “invisible” in situations where one doesn’t want to be noticed. This could be used in astral journeying as well as in daily life. It is also said to be able to help pick up thoughts and feelings and enhance them. It is also a protective stone, said to be particularly protective in dangerous places. Opal is used in lightwork as a stone for strong and safe dreamwork.
Emotionally, opal brings its water energy to enhance self-esteem and sense of self-worth. It can help bring these to the surface of your life in spite of anything else going on under the surface. This aligned with the inspiring love energies can help you release damaging inhibitions and access your true spiritual nature. Opal is also used to bring happy dreams and avoid nightmares. It is a soothing stone which can calm turbutlent emotions and bring a deep sense of hope and inner peace.
Opal is said to be a stone for love. It brings the inspiration of love into a stagnant heart chakra and brings renewal. This can take the form of fiery sensual love or gentler unconditional love and any shade of love in between. Opal is also said to bring fidelity to love.
Traditionally in crystal healing opal has been considered good for headaches, eyesight, Parkinson’s disease, blood, insulin regulation, PMS, and the immune system. Note that healing crystal meanings are spiritual supports to healing and are not prescriptions or healthcare information.
Opal is often associated with the Heart Chakra and Crown Chakra, but varied color opals are also related to the additional chakras.
All types of opal tend to share these energies in common, along with their own spiritual and unique energies.
Opal Jewelry Ideas
Precious Opals are cut and polished into cabochons and used in all forms of jewelry, especially as pendants and ring centerpieces. Fire Opals are faceted into several gemstone cuts for jewelry. Boulder Opal is also a popular form which is used as jewelery, especially as cabochons. Opal, especially Common Opal, can also be carved into small ornamental figures.
Taking care of opal is easy. All it takes is a little bit of common sense and knowledge about opal. Before deciding how to best care for your opal you need to be aware of the type of opal you have;
- Doublets – Doublet opals consist of two layers, a thin slice of opal and a black backing. The slice of opal is cemented to the backing in order to enhance the colour.
- Triplets – Similar to doublets, triplets also include a third transparent layer on the top (quartz or glass) to protect the opal and give it a rounder shape.
- Solid Opal – Natural solid opal which has only been cut and polished.
Solid Opals – Opal is a soft stone, approximately the same hardness as glass (around 6.5 on Moh’s hardness scale), so it is important to treat your opal carefully in order to avoid damaging it. Remove your opal jewellery if there is a chance it will be scratched or broken (i.e. working in the garden, moving furniture, etc.)
Many people believe solid opals can be damaged by water – however, this only applies to doublets and triplets. Solid opals are fine in water. In fact, most precious opals contain about 5-6% water. As a result, opal may crack if subjected to very dry conditions or rapid changes in temperature. Try to avoid very high temperatures or low humidity extremes, such as boiling water or zero humidity bank vaults.
Doublets & Triplets – Caring for doublets or triplets is a little different to caring for solid opals. Because doublets and triplets consist of multiple layers glued together, prolonged exposure to water will eventually cause lifting between the layers and the infiltration of water. A doublet or triplet will take on a ‘foggy’ or grey appearance if this happens. This does not mean your opal will be ruined if you wear it in the shower once, or are caught in the rain. It takes prolonged exposure to cause water damage to a doublet or triplet.
Solid opal should be cleaned gently with mild detergent in warm water and a soft toothbrush or cloth. Avoid bleach, chemicals and cleaners. Doublets & triplets may be wiped with a damp soft cloth and mild detergent, but should never be soaked or immersed.
Never allow anyone to clean your opal in an ultrasonic cleaner, as the intense vibrations may cause cracking in a solid opal, and water penetration in a doublet or triplet.
If your stone loses its shine or becomes scratched, bring it back to an opal cutter. After years of wear, small scratches and scuff marks cause an opal to lose its shiny polish and become dull looking. Professional polishing can bring new life to an opal which has become dull or scratched, and we can also check for claw damage and ensure the security of the setting.
If you need to store your opal away for a period of time, simply place it in a padded cloth bag for protection and store it away. For longer storage periods, place your opal in cotton wool with a few drops of water, then into a sealed plastic bag just to be safe. The water is not intended to soak into the stone (as opal is impervious) but will prevent water coming out of the stone if it is exposed to very low humidity environments (for example, zero humidity storage safes).
Opals are delicate, but well worth the care. Their most significant weakness has to do with the water content. If an opal is allowed to dry, it will crack and craze. In most cases, they do not need any special care while stored. However, if you live in a very dry climate, or keep them in a dehumidified room, some precautions are necessary. Keeping them in a tight plastic bag, with a damp piece of cotton or fabric will prevent dehydration.
Storing an opal in oil or glycerin is not recommended. It is unlikely to damage the opal, but it is unnecessary and requires tedious cleaning.
Because of their water content, opals are also highly sensitive to sudden changes in temperature. I know of a woman in Pennsylvania who wore a brooch on the outside of her coat. As she passed from the warmth of her house to the winter cold, there was an audible “crack” as her opal self-destructed.
Opals do not mind being hot or cold, it is the rate of change that damages them. You need to avoid situation like the one above, going from a warm house to the winter’s cold. Simply wearing an opal under clothing will protect them. Also, do not store opals near a heat source, an open window, etc., where they can be exposed to sudden temperature changes.
Being somewhat soft, they scratch easily. Realize that a large component of dust is quartz at 7 in hardness. At 5.5 to 6 in hardness, simply wiping the dust off an opal will gradually reduce its polish. The solution is to clean your opals using a soft cloth or brush, a mild detergent, and room temperature water. Then rinse the jewels to remove any residue. Clean doublets and triplets with the same method, but do not soak them. Soaking can dissolve the glue holding the layers together.
Prevention is the best solution to scratching and chipping. Opals are best suited for earrings, brooches, and pendants. These jewels receive little contact with harder objects, compared to what a finger ring experiences. If you do get an opal ring, choose a setting that protects it from coming in contact with other objects.
Understand that, if you wear an opal ring on a regular basis, it will require occasional repolishing. Reserving your ring for special occasions will greatly reduce the risk of damage.
Make sure you remove your ring before physical activities like gardening and sports. Also, do not immerse the gem in liquid chemical solutions, like dishwater. Opals are porous and absorb liquids.