With some of the basics out of the way, we are finally going to discuss some of the characteristics of natural solid opals. Characteristics like brightness, diffracted color, patterns, play of color, and cuts. We are also briefly discussing damage to and cleaning opal jewelry.
Brightness
There is a brightness scale used to evaluate opals. It ranges from Faint (1) to Brilliant (5). The brightness refers to the play of color in the stone. The brighter the fire, the more the stone is usually worth.
Diffracted Color
Diffracted color refers to the colors the opal shows in its fire. Opals are capable of diffracting the light in every color of the spectrum. Blue and green are the most commonly observed color of fire. While orange and red are the rarest colors. The colors are listed in order from the most prized to the least: red, orange, yellow, green and blue. Usually a stone fires primarily in one color with a secondary color. If the stone fires with more than 3 colors it is a multicolor opal. The rarest precious opals are the deep black opals with red fire. The most common are the precious white opals with green fire.
The opal in this ring (pictured below) fires with more than three colors, so it is a multicolor white opal. The main fire color is pink, but there is green, violet and yellow. It is really hard to take pictures of opals (if you don’t believe me, try it sometime), so I was only able to capture the pink and one green burst of fire. The other colors are there, but they didn’t show up in the photo. This ring was given to me by a friend, it comes from my personal jewelry collection, but I wanted to show you the fire in the opal. Who knows you might find one of these at a yard sale, but it won’t be at my yard sale.
White Opal Sterling Silver Ring. Notice the play of color (fire). There are more than 3 colors, so it's a multicolor white opal.
Pattern
Patterns refer to the diffracted color pattern in the opal. Some of these patterns are quite rare and valuable, like the Harlequin (which resembles a checker board). Here are some of the pattern names: Harlequin, Floral, Pinfire, Palette, Peacock Tail, Jigsaw, Chinese Writing, Moss and Rolling Flash. All opals have their own unique pattern; these are just patterns that names were given to. Sorry I don’t have any pictures to show you, because I don’t own any opals with these patterns. If I did own them all, I would be rolling in the opal dough (so to speak), since they are expensive opals.
Play of Color
This refers to the combination of factors in the opal, such as the brightness, the color range of the diffracted color, the pattern, consistency of the play of color over the entire opal’s face and the direction the play of color is visible from as the stone is rotated. All of these factors produce the play of color opals are known for. The better the play of color, the rarer the colors, the intensity of the color usually equals a more expensive opal.
Cut
The cut of the opal is also important. The domed oval (cabochons), pear, and regular shapes are the most expensive cuts. The irregular shapes (freeshapes) are not as expensive. Remember, this is assuming all the other qualities are equal. There are irregular opals that are worth more than the opal cabochons, because the stone’s characteristics are higher quality.
Opals can even be heart shaped. These opal heart shaped earrings are white opals with a slight green play of color. These opals are from my personal jewelry collection, they were given to me by a friend, which makes them priceless. You wouldn’t find them at my yard sale either.
White Opal Heart Shaped Earrings with a slight green play of color (which you can't see in the picture).
Damage
If there are cracks that reach the surface of the opal, it renders the stone virtually worthless. You have to treat opals carefully, since they are fragile. Each opal contains a different percentage of water. If the water is lost, the stone can crack. Be careful around heat and extreme cold temperatures, as they can hurt opals by reacting with the water contained in them.
Cleaning Opal Jewelry
Clean your opal jewelry, using opal safe methods. These are room temperature water, a mild detergent (with no abrasive particles), and a soft cloth. Make sure there is no dust on the opal before wiping with the cloth to dry it. Be very gentle as opals are very delicate, you don’t want to scratch them. Remember, they are porous and soak up chemicals. Therefore, harsh jewelry cleaners are too much for an opal and damage them, so be very careful. Also store your opals in a moist absorbent cotton wool cloth sealed in a plastic bag. This helps prevent them from drying out and cracking, especially in dry climates. Do NOT put your opal in HOT water or COLD water; they are very temperature sensitive.
Remember, these are just guidelines when cleaning your opal. If you are worried about possibly damaging your opal, have it cleaned by a professional jeweler. If I had an expensive opal or a sentimental piece of jewelry with an opal, I don’t think I would risk any of these cleaning methods, I’d take it to a jeweler for cleaning. However, it is your choice and your opal.
Please note, I’ve only covered the very basics of opals in this four part series. I wanted you to be familiar with opals, since they might be encountered on your hunts for precious metals. After all, opals are included in precious metal jewelry.
There is a lot more to them. If this series peaked your opal interest, then the articles did their job. Have fun continuing your researching. If you learn anything you want to share with us, please leave a comment on this article series. We would love to read them.
Want to read the third article in this series, you can read it here – Precious, Fire and Common Opals. Did you miss the second article in the series, you can read it here – Opal Doublets and Triplets? If you missed the first article in the opal series, you can read it here – Imitations, Not Gemstone Quality and Synthetic Opals.
Good Luck and Happy Hunting,
~Vicki Priebe Author of "Cheap Gold and Silver"