All About Opal – Uses, Properties, Color, and Worth

What is Opal?

Opal is an amorphous mineraloid, or non-crystalline solid. It is highly sought after by many as a gemstone due to its ability to come in many beautiful colors. Opal is a silica based mineral that does not actually carry color but reflects light instead.

Opal forms by liquid entering into the cracks of almost any kind of rock and depositing the silica contained within the liquid.  At lower temperatures and long periods of time, this silica will solidify creating opal.

Opal falls in the 5.5 to 6 on the Mohs scale of hardness, which makes this stone capable of cutting and faceting to jewelry.

There are two classes of opal that are found today.  Common opal is as it sounds, it is more commonly found throughout the planet.  Being so common, it will also have commonality of color.

Common opal does not typically have a pretty array of colors.  Common opal can definitely have its charm and still carry some value as it will still be used in various applications as jewelry.

The second class of opal is precious opal. This is the opal many look for and can carry some greater value.    

What is precious Opal?

Precious opal is a more precious and rare form of opal. It has what is called play-of-color, or iridescence. Precious opal is a phenomenon of colors from the light spectrum reflecting on a silica surface.

This phenomenon is similar to what you would see on a soap bubble floating through the air reflecting light.  Imagine an array of silica spheres with empty voids taking in white light. The light is refracting different colors of the visual spectrum, which is what precious opal does.  

Those visual spectrum colors seen in opal will be due to the varying sizes of silica bubbles and spacing.  Smaller bubbles would produce more blues, as larger bubbles would produce reds.

There are many sources for opal in the world, but as far as precious opal goes, Australia is the major producer of precious and valuable opal.  The largest valuable opal found, called “Olympic Australis” was found in Australia weighing in at 17,000 carats.

What is the color of Opal?

The color of opal can be colorless, milky white, milky greenish and bluish, yellow, grey, and brown for more common opal.  With precious opals the colors are typically in respect to the visual spectrum, such as a rainbow, and also include the very rare color of black.

For the most part, people tend to be more interested in the precious opals.  Although the common opals can be quite beautiful in color, seeing the color of the visual spectrum in precious opal can be breathtaking.  Black opals are considered the rarest type of opal that can be found. 

Though blues, greens, and purples look very nice on an opal, the brighter colors such as yellows, oranges, and reds are a bit rarer and do fetch a higher price.  Some of the most beautiful examples of precious opal will contain all the colors on the visual spectrum.

What is Opal used for?

Opal is used primarily for jewelry such as rings, pendants, necklaces, earrings, and other fine jewelry.  Opal can be used as specimens cut as cabochons and also sold as a loose rock as well.  Some other opals such as fire opals can be cut and faceted like other gemstones.

Common opal can be cut out into figurines and other small objects and displayed.

Some people believe that common opal combines earth and water energies and when worn or carried, they help the balance of your energy.  Others believe that opal can even protect you from negative energies.

What is Opal worth?

The worth of opal will be determined by the colors, size, patterns seen, and brilliance of the opal.  Rare opals can be valued at $20 a carat to over $1000 a carat. Some of the more rare colors of black and red have been known to be worth $1000’s per carat.

A beautifully cut Australian jelly opal, containing the color red and weighing in at 3.36 carats, can run you upwards of $5K USD.   The most precious opal, black opal, which can be considered the most prized of all opals, can cost you upwards of $10K USD per carat.

The rarity of colors such as the color black and how much that rare color is displayed in the stone, will play a big factor in opal worth. If there are multiple colors in the opal stone you can expect some higher prices as well.

Opal can be a very difficult gemstone to price as there are so many different varieties and patterns available. Color and pattern is the most important factor for this gemstone, but keep in mind not to forget the size. The larger the opal the more it will be worth to the point of exponentiation in value.

Why is opal so expensive?

Opal is expensive due to the rarity of precious opal and high demand of the very colorful gemstone.  Precious opal, unlike common opal, is not in abundance on our planet making it very expensive.  Many lighter colors such as yellows, oranges, and reds will be even rarer, which can drive up the expense on opal.

Where can Opal be found?

Opal can be found in several places around the world including; Austraila, Brazil, Honduras, Mexico and in the USA states of Nevada and Idaho. Opal will be where there has been recent volcanic activity, in hot springs, and all types of heavy silica sediment environments.