Opal happens to be one of the most breathtakingly beautiful gemstones in the world; and there is of course, a solid reason why. The ever-so-striking opal is known to form from the rain. While there isn’t a common consensus on how opals are created, many like to believe that these precious gemstones are formed by rain. The rainwater seeps down into the cracks of the rocks. When the water evaporates, the silica is left behind which dries out with time and thickens into a gorgeous opal.
However, in ancient times, the ancient Greeks called opals as “Opallios” which means “to see a change of color” and were believed to be formed from the happy tears of Zeus when he defeated the Titans. It was further believed that the opal could also impart prophetic gifts and powers. Therefore, this gemstone is considered as a lucky stone by many civilizations.
What really sets opals apart from other gemstones in the world is its more-than-meets-the-eyes quality. Opal consists of thousands and millions of silica spheres in different colors and sizes. These silica spheres deflect beautiful spectator of colors that are an absolute feast to the eyes. What is more incredible is that opals come in different types, each of them showing off their distinctive beauty in their own way. In this blog post, we have compiled some of the popular types of opals that are worth your read.
Table of Contents
- Australian Opals
- African Opals
- South American Opals
- Indonesian Opals
- USA Opals
- Other Types of Opals
“Black Opal” is a type of opal that has a dark black or gray body color. The term is also used for opals that come in dark blue or green body tone. There is a small but famous town in Australia – Lightning
Ridge – that produces this wonderful gemstone. History tells that the first Black Opal was founded in Lightning Ridge in 1873. However, it wasn’t until 1903 that people started realizing its indescribable value.
From that era till now, Lightning Ridge is the only place where this magnificent stone is produced and sold. While black opals have a darker base, there are also black opals that may feature different hues on both sides. Such types of black opals are called as “reversible” opals.
Many mistake fire opal with precious opal but they are poles apart. Fire opal is a type of opal that boasts a bright yellow, orange, and red color. While fire opals are mainly found in Australia, these highly-prized gemstones are also excavated in the cast mines of Queretaro, Mexico. You can also find these stones in Honduras, and the United States of America where other more precious kinds are known to be easily found.
These fragile stones come in fiery colors and hence the name “fire opal”, a Mexican fire opal, however, is different. Mexican fire opals are transparent or translucent in color that can come with or without yellow, orange, or red body color. Ever wondered what makes this expensive gemstone fiery in its color? It is the iron content in a high quantity!
Although dark opal extrinsically has a dark base, it isn’t dark enough to be called Black Opal. In other words, it is a semi-black opal that is darker than white opals. Like Black Opal, these valuable stones are also found at Lightning Ridge. In addition to Lightning Ridge, dark opals have been found at Mintabie – an opal mining community in South Australia.
Also referred to as “milk” or “milky” opals, Australian white opals feature light or pale white body shade. Like any other opal in the world, white opals have the ability to portray different specks of colors at once.
Often times, white opals have a transparent or colorless back but some opals can contain a range of beautiful colors too. Since they have pale body tone, white opals are less bold and vibrant than other kinds of opals such as black opals or fire opals.
Even very white opals consist of a pale tone and despite their paleness, are exceedingly beautiful and can cost upwards of AUD $200 carat. White opals are the least valuable variety due to the fact that they are the most common variety of opal.
After Black Opal, boulder opal is the second-most valued opal in the world. Due to its dark body tone, boulder opal is often mistaken for Black Opal.
It is a type of precious opal that is distinguished by its brown ironstone on the left side of the stone’s back. Boulder opals are prepared in the combination of ironstone which is why they are mined from ironstone boulders, well below the ground.
During their formation, thin and pretty creases begin to form in the cracks of the stone. These thin veins can form in any beautiful color and spread out all around the stone, giving it a distinguishable appearance. Since the ironstone provides a dark-shaded back to boulder opals, the precious stone typically has a vibrant dark body color.
Boulder opals can only be found in the state of Queensland, Australia. Some of the most prominent opal fields in this town are Winton and Quilpie.
Within the sphere of boulder opal lays some types of opals that are worth the discussion:
Koroit Opal is a type of opal that is popular for its exquisite ironstone that consists of gorgeous patterns and different hues. They are also larger in size and more valuable than any other kind of commonly-available opal.
Koroit started to form when Lawrence Rostron – a manager of a local property – found out the Koroit Opal Field in 1897. Owing to its diversity, Koroit Opals are popularly used in pendants, rings, and earrings.
Yowah nuts opals are a rare specimen produced in a small mining area in the Southern region of Queensland, Australia. Bryan Rossiter discovered a mining field – the Southern Cross Mine – which got registered in Yowah on Sept. 1, 1884.
Yowah nuts come in a spherical or ellipsoidal shape that can reach up to the size of 20 cm across. Yowah nuts display a remarkable play of colors, exhibiting flares of green, blue, purple, red, yellow, and orange. Typically, this type of opal has one half of its body in white color and other half in blue which makes it all the way more unique.
Matrix opal comes from two different mining fields – Queensland which is a field in the northern part of Australia and Andamooka in South America. The type of matrix opal that comes from the Queensland fields is left untreated which eventually forms into colorful ironstone with streaks of opal on them.
In the second type of matrix, the opals are treated to give a dark backdrop. The treatment includes the soaking of stones in sugar solution which is followed by acid boiling. As a result, carbon produces deposits in the small spaces of the rock. This helps give the stone a dark body color like black opal.
While Australia has been the number one producer and seller of opal for over 100 years, slowly and gradually Ethiopia is coming on as the second most dominant force in the opal market. The first-ever opal in Ethiopia was discovered in 1994 in the Menz Gishe District in the Shewa Province, followed by more discoveries in 2008 near the town of Wegel Tena in the Wollo Province and 2013 in the Wegel Tena area in the Wollo province.
The most appealing factor about Ethiopian opals is that they are more affordable than Australian opals and have the same quality wise as of Australian opals.
2. Tanzanian Opals
Besides Ethiopia, another region in Africa where opals are mined is Tanzania. The most popular Tanzanian opal is Tanzanian Green Opals or Tanzanian Honey Opals. Did you know that green opals share a resemblance with Jade and is called as Prase opal?
Green opals also have a great symbolic meaning related to money and success. It is also considered beneficial in relieving stress, improving vision, and controlling high blood pressure. To be specific, Tanzanian green opals are found in Mount Lyobo and may consist of a nickel variety that boasts a bright bluish-green color.
South American Opals
While opals are famous for their striking play of color, there is also a distinctive variety of opal that displays the burning glow of fire – Mexican opal. It comes in bright red and orange color that instantly captivates the attention of the beholder.
Mexican opals are commonly mined in the Mexican states of Hidalgo, Guerrero, Julisio, Queretaro, Michoacan, Chihuahua, and San Luis Potosi. However, the most significant mines are situated in Queretaro. Mexican fire opal was first discovered in 1835 and continues to be produced till date. These opals contain a high level of water which is why it should be preserved against heat and strong natural and artificial light. Otherwise, this stunning stone can dry out.
Brazilian opals are generally mined in the North East of the Piaua, in a small mining field using a generator. These opals are distinguished by their crystal patterns, having soft, feminine colors. As compared to other opals, Brazilian opals have low moisture which is why they are hardly considered as an opal.
Brazilian opals are formed in thin layers and in alluvial deposits that are washed down by rivers over hundreds and thousands of years and are mined on slopes of Opal mine in the Horca area of Brazil. Although Brazilian opals are extremely unique from Australian and Ethiopian opals, they are found in low quantities since the production is slow due to lack of investment in the field.
Fun fact: Peruvian Opal is known as the national stone of Peru.
This type of opal is relatively uncommon and found only in the Andes Mountain. Unlike other common opals, Peruvian opal is deprived of color play or fire. It is a sedimentary rock that is formed from an igneous rock at low temperature. The chemical composition of Peruvian opal includes oxygen, hydrogen, and silicon while silicon present in the highest content.
You can find Peruvian opal in two types – blue Peruvian opal and pink Peruvian opal. Due to high water content, blue Peruvian opal comes in the cool blue shade and is also sensitive to heat. Exposing these opals to extreme sunlight may make them lose their intensity and break eventually.
On the other hand, pink Peruvian opal boasts a baby to bright pink shade and is also found in Western Australia. It is also known as pink Andean Opal, Andean Opal, and Angelskin Opal.
Sometimes referred to as Honduran black opal, this crystal black opal is distinctive due to its unique colors. You can find this variety of opal from a milky-white color to a black-base one. It is believed that Honduran opals are formed by volcanic eruptions which usually occur in South America.
While Australia is famous for having the world-class opals, Honduras is known for possessing the oldest opal mines in the world. The Central American country houses the world’s oldest opal mine – Tablon mine.
It should be noted that Honduran opals are not like the normal opals that you may be used to seeing online or in magazines. These opals are made from the combination of opal and sandstone which is unlike the production of other types of opals.
There was a time when the country featured volcanic opals mined in Kalimaya River in Java and Banten Indonesia. These opals flaunted black body color with flashes of vibrant colors like red, yellow, and green. However, you should know that most of these black opals listed and auctioned on many websites aren’t natural black opals. They are Ethiopian opals that are treated to give them a black outlook. Generally, these Ethiopian opals are put over a fire in a box until smoke starts to penetrate into them as they are heat absorbent and therefore ultimately changes into a black color.
Today, Indonesia mostly feature lime green opals, mined and transported from Ethiopian Opal fields – one of them known as Kalimay Black Opals.
You can find a wide variety of opals in the United States from Idaho to Arkansas to the Virgin Valley, Nevada. While different regions are famous for different kinds of gemstones, Nevada is a single state that is distinctly known for opals, especially yellow fire opals.
Moreover, some of the world’s best black opals come from Nevada after Australia. The other notable states where opals are mined include Louisiana, Idaho, Arkansas, Utah, Oregon, and Arizona.
Other Types of Opals
1. Dendritic Opal
It is the type of gemstone that has the power to change your luck and bring light to the darkness. In appearance, it has a milky base with black dendritic that looks like moss or fern.
2. Opalized Wood Opal
This is the type of opal that was timber or vegetation millions of years ago and after opalization, it converted into wood opal which is also known as USA opal and boulder opal.
3. Hyalite Opal
It is a transparent opal and is typically found in Australia and Mexico.
Opals come in such a great variety of origin, shapes, colors, and sizes that it is hard not to fall in love with them. We couldn’t agree more with their world acclaimed title – the Queen of Gemstones!