Opals are one of the most interesting gemstones because they have such a wide range of species and prices. You can find common opals with prices as low as 20$ a carat to black opals at 10k a carat. In this blog we will cover everything from the different types and colors, how to identify them, maintenance and cleaning, hydrophane opals and everything you need to know before you buy one!
So first let's start with the basics! Opals have a hardness of 5.5-6.5 on 10, meaning it is a softer stone and does require more care. You have precious opals, which means the stones have iridescent color play (the flashes of color within the stone). If they don't have any and are opaque they are known as common opal.
If you are looking to buy an opal, an opal engagement ring or jewel, send us an inquiry and we will be happy to send you a wide range of selection to choose from!
What Causes The Color In Opals?
The colors within opals are caused by the tiny spheres of silica within the opal. When light diffracts on these spheres as it travels through the lattice, a ray of colors appear. The smaller the sphere, the smaller the wavelength and as a result, the range of color. For example, the smaller beads will only show greens and blues because these colors have the shortest wavelength. The larger ones will show more colors, such as red, which takes the largest wavelength to be produced. This makes red a desired color to look for when buying.
When buying an opal here are the most important things to know.
1) The range of colors within an opal is a huge contributor to pricing. The wider the range of color and pattern within the stone, the pricier the gemstone. If the opal's colors are light and subdued, this can decrease the value.
2)The pattern within an opal. Not only do you want to look for a wide range of color but also in what way the colors are arranged. What causes an opal to have a pattern is how the spheres of silica are aligned. When they are perfectly uniform within the stone you will find beautiful patterns, which is uncommon. Additionally, if the pattern is consistent through the stone and with out dead zones, (parts of the opal that have no color or have impurities) it will increase the value.
3)The purity of the opal. Opals are broken down into 3 categories. You have solid opal, boulder opal and matrix. Solid opal is exactly as it sounds, its entirety is solid opal. It is the most valued. Next you have boulder opal that is found through other stone in patterns which resemble veins. Matrix opals have other types of stone mixed through the opal in patches.
4) A very important thing to know when buying opals is knowing when the opal has been cut. This is because when opal has been freshly mined, it is not yet stable. They need a period of up to 3 years to dry out before they are sold. If they don't have a proper drying time, they may actually change color and transparency. You know this has happened when your opal that was bought with a translucent appearance has slowly turned foggy or milky after several months. In some cases the colors can even turn to less desirable shades. All good vendors should be aware of this gestation period and should be able to provide you with the dates for their gems.
Australian Black Opal
Australian black opal is the most sought after opal. It is more rare to find a high quality black opal than a quality diamond. An Australian opal of top quality can easily go for 10K a carat.
When buying a black opal the 3 most important things are:
1) The pattern or sequence of the color. The most desirable pattern is called Harlequin.
2) Australian opal has a base color that ranges from white all the way to black. The closer you can get to a uniform black base, the higher the quality. A black base paired with a consistent and vibrant color scheme through out the stone is a rare & desired find!
White Opal
White opal, the most commonly known opal can be opaque or translucent and has a nice range of color play. Commonly sourced in Ethiopia, its prices can range as low as 20$/ct to 1K$/ct.
1) When buying cabochons, you want to make sure the opals are well rounded, to not affect the color play of the stone.
2) You want to buy opals with intense color, equally dispersed throughout the stone.
Mexican Fire Opal
Mexican fire opals are, as the name suggests, found in Mexico. They can also be found in Guatemala, Canada, the US, and even Australia. They come in colors ranging from white to yellow, orange, and red.
1) The more saturated the color the more the value will increase and colors such as red and oranges are the most desired.
2) Higher quality material will have color play. However with Fire Opal you wont see as wide of a spectrum as white opal or Australian black opal. Often the only 2 colors that may occur are greens and blues.
Common opals
Common opals are the species of opals that are the most common and in abundance, however they aren't the most commonly known. This is because they don't have iridescence, making it a less desirable stone option. Peruvian opals have very unique colors such as turquoise, pinks, blues, purples and range in translucent to opaque.
Doublets, Triplets & Mosaic Opals
Doublets, triplets & Mosaic opals are opals that are "man made". They are an option if you want to have a higher quality opal but at a more affordable price. They often range from 10-100$ a piece.
Doublets are formed by taking a very thin layer of natural opal and sticking it onto a base. These bases are often made of another stone, such as sand stone, or when trying to imitate black opal they may use onyx.
Triplets, like doublets are made with a stone base but also have a top layer added onto the thin layer of opal, almost creating a sandwich effect. The top layer is often made of a transparent quartz or glass and can help protect the opal.
Mosaic Opals are composed of a sand stone base, but instead of a thin sheet of opal, they are made with small fragments of opals stuck together, forming what resembles a ceramic piece.
What are hydrophane opals?
Hydrophane opals are opals that have a higher porosity and will absorb water, when in contact. You can easily spot a hydrophane opal because when placed in water, they will become transparent and their colors subdued. If you do have one, do not worry, these changes aren't necessarily permanent. If it has happened to you, simply remove your ring and let your opal dry away from direct sunlight. After a few days it should return to normal.
Once you've discovered you do have a hydrophane opal, we do recommend removing it when in contact with water because coming into contact with water a few times is fine but doing this constantly can cause damage to your opal and permanently fade the colors.
Are opals a good choice for an engagement ring?
Yes and no. As mentioned earlier in this article, opals are quite soft. They have a hardness of 5.5-6.5, making them a risky choice for every day wear and tear.
You will have to be prepared to have it re-polished every several years to remove the superficial scratches. Especially if you choose a more translucent opal, these scratches can cause your opal to look opaque.
Opals can be bought in cabochon and in faceted. With faceted stones you will also have to have the facets re-polished because their soft edges will wear quickly, leaving the stone looking worn down.
If you are interested in creating an opal ring or engagement ring, send us an email at info@fineandflux.com and we can help source any quality and specimen of opal your looking for!
How To Clean & Care For Your Opal Jewelry
Cleaning opal jewelry is really quite simple. First you can let your jewelry soak for several minutes in lukewarm water. This will help break up any accumulated soap or cream residue. Then you can go in with an old tooth brush and scrub in and around the opal. Do make sure the soap you are using is unscented because the alcohol in the perfume can be harmful to the stone.
Identifying Fake Opals
The most common type of synthetic opals are Gilson opals. They are commonly seen on the market and, in some instances, can be hard to distinguish from the natural gemstone. Let's have a look at how to differentiate them from the natural!
1) The easiest way to differentiate Gilson Opal from natural is by turning the stone sideways! The formation in which Gilson opal is formed is almost like tiny strands all stuck together, forming a block. When looking face forward, the synthetic opal could look strikingly similar to natural but when looking near the side of the stone, these strands are not a formation that naturally occurs in opal.
2) When moving natural opals, the color play should disperse throughout the stone like water. With Synthetic, the color will not move throughout the stone, but stay within the same place.
What Are Andamooka Opals?
Andamooka opals are a type of opals found in Australia. This type of opal is almost always treated. They subdue the opal in sugar water and then acid. The sulfuric acid will turn the sugar to black carbon and, as a result, the base of the stone itself will also turn black. In darkening the base of the opal it will allow the color play within the opal to show a more striking contrast and as a result the colors will pop!
You can distinguish Andamooka opal by its pin points of black spots throughout the stone. This type of color spotting does not naturally occur.
At Fine+Flux jewelry we specialize in personalized fine jewelry and engagement rings. We can helps source any type of opal or gemstone you may be looking for! Reach out today to request a free quote and get started on your dream jewel!
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