Welo vs. Australian Opal – what are the differences?

Opals are among the most fascinating gemstones of all, famous for their dazzling color and unique beauty. For a long time, Australia was considered the almost exclusive source of high-quality opals. But since the discovery of Welo opals in Ethiopia, the world of opals has expanded significantly. This blog post highlights the differences between Welo opals and Australian opals in terms of origin, formation, appearance, stability, jewelry processing, care, market value, and trends. 

1. Origin and locations of Welo and Australian opals

The origin of an opal significantly shapes its character. Welo opals come from Ethiopia – more precisely from the highland region of Wollo in the north of the country. The first precious opal finds in Ethiopia date back to the 1990s (Shewa region/North Shewa). However, these early Ethiopian opals often tended to craze (fine cracking) and were brownish in color, which meant they were not very popular in the trade . A breakthrough came in 2008 with the discovery of a large opal deposit near the town of Wegel Tena in Wollo. These new opals – now known as Welo opals – were characterized by their light-colored base material and vibrant color, similar to traditional Australian opals. With around 1500 kg of material mined in the first few years alone, Wollo quickly became a significant source of opal, and Ethiopian opals established themselves on the global market.

Australia, on the other hand, is the classic home of opals. Significant opal fields were discovered there as early as the late 19th and early 20th centuries – famous examples include Lightning Ridge in New South Wales (the main source of black opal) and Coober Pedy in South Australia (known for its white milk opal). Until the discovery of Welo opals, Australia accounted for around 90–95% of global opal production. Even today, the most valuable and expensive opals mostly come from Australian mines. The country has many varieties: from black opal from Lightning Ridge to crystal opals and boulder opals from Queensland to white opals from Coober Pedy. These regional origins are synonymous with opal quality and variety. Australia's long opal tradition has led to "Australian opal" being considered a synonym for quality – with corresponding prestige in the trade.

In summary, Welo opals are a relatively new discovery from the mountains of Ethiopia, having only entered the market for approximately 15–20 years. Australian opals, on the other hand, have been mined for over a century and historically dominate the market. This diverse origin is reflected in the geology and properties of the opals, as we will see in the next section.

2. Geological origin and structural differences

The geological formation of an opal influences its appearance and stability. Australian opals predominantly formed in sedimentary rock layers. Millions of years ago, shallow ancient seas covered large parts of Australia. In the dried-up basins of these ancient seas, siliceous water seeped deep into the soil and filled cavities and cracks in the rock. Under low geological pressure and at low temperatures, the dissolved silicon dioxide was deposited in the form of tiny spheres that aggregated to form opal. This process took place in sandstone and mudstone , often in association with iron-bearing rocks (for example, boulder opal, which occurs in an ironstone matrix). Australia's opals therefore grew deep in the earth , in places that were once rich in water. This explains why Australian opals naturally contain water , but in a stably bound form (no free water in pores) .

Welo opals from Ethiopia, however, have a completely different geological origin. They form in volcanic rock . In the Wollo region, the deposits consist of volcanic tuff and rhyolite layers in the highlands (sometimes at 2,500–3,000 m above sea level). Silicon-rich hot solutions penetrated cavities and cracks in basalt and rhyolite , depositing silica in gel form . Upon cooling, this hydrated silica gel solidified into opal. Welo opal is often found as nodules or veins in the volcanic rocks . The opals themselves formed relatively close to the Earth's surface, where formerly active volcanoes and hot springs provided the silicon dioxide solutions. Geologists refer to Welo opal as opal-CT , which indicates its crystalline structural variant (cristobalite/tridymite component). – typical for opals from volcanic regions.

One key structural difference arises from their formation: porosity . Welo opals are often more porous (sponge-like structure), which gives them a hydrophane property – they can absorb water. The microscopic pore spaces are a result of the rapid cooling of the siliceous gel and the shorter geological ‘maturation time’. Australian opals, formed over much longer periods of time and deeper in the earth, are denser and less porous. However, both types of opal are made of amorphous silica and display the characteristic sphere packing structure : countless submicroscopic silica spheres in a regular pattern. This ordered network refracts and reflects light, creating the famous play of color in opals. The basic chemistry is therefore the same for both – SiO₂ nH₂O , an amorphous silica structure with a variable proportion of water .

In short: Australian opals are sedimentary and geologically “old”, while Welo opals are of volcanic origin and comparatively “young”. 

3. Play of colors, transparency and appearance

Both opal types impress with their play of colors, but there are differences in their appearance :

Welo opals typically have a light to colorless base color (body tone), ranging from milky white to yellowish to transparent. Many Welo stones are so-called crystal opals —meaning they are translucent to see-through. This transparency often enhances the visual impression of the play of colors, especially when light hits them from behind (known as the contra-luz effect, which makes the opal's fire visible in transmitted light). The play of colors itself can be extremely vivid : strong red, neon orange, green, blue, and even violet shimmer in the same stone. 

Some Ethiopian opals display unique patterns , such as the coveted "honeycomb" pattern , in which the colors appear arranged in hexagonal fields. Such patterns are rarely found in Australian opals. Overall, Welo opals often have a vibrant and modern appearance—their clear, colorful fire against a light background gives them a strikingly brilliant appearance.

Australian opals come in different varieties , which greatly influences their appearance:

• Black Opal : This is considered the king of opals. It has a dark (black-gray to deep blue) base color, against which the bright colors create an extremely high-contrast effect. A black opal, for example, can display red and green flashes against a black background—as if a rainbow were shining in the night sky. Lightning Ridge is famous for such specimens. Black opals are usually opaque (not transparent) and sought after for their dramatic appearance.

• White opal (milk opal): Light, opaque base color (whitish, milky) with often more pastel color play. These typically come from Coober Pedy. The color play is present, but due to the light background, it is somewhat more subtle than in black opals. White opals appear elegant and have softer colors.

• Crystal opal : Transparent to translucent opals (found in Australia, for example, in South Australia or Queensland). They are somewhat similar in appearance to Welo opals, as they allow light to pass through them. Flashes of color then appear to emanate from deep within. Australian crystal opals usually have a light body tone.

• Boulder opal : These unique stones from Queensland have a portion of the brown parent rock matrix (ironstone) on the reverse. The opal layer is thin and intergrown with the rock. The play of colors of a boulder opal stands out against the dark rock background, allowing it to shine with a similar contrast to a black opal. At the same time, boulder opals often exhibit interesting shapes due to the irregular opal veins running through the rock.

Regardless of the variety, high-quality Australian opals exhibit intense coloration ("opalescence") with all colors of the spectrum. However, certain shades are more common depending on the location – for example, Coober Pedy opals often exhibit more green and blue, while black opals from Lightning Ridge more often contain fiery red (which increases their value).

4. Processing and suitability for jewelry

Both Welo and Australian opals are generally suitable for jewelry making, but there are a few differences in processing and use .

Cutting and processing: Australian opals are traditionally cut as cabochons – that is, with a smooth, domed top and a flat back. This cut optimally emphasizes the play of color and preserves as much material as possible (important for expensive opals). Doublets or triplets are often produced, especially for thin layers of opal (e.g., boulder opal) or opal sitting on a light potch layer. A thin layer of opal is then placed under a dark background (slate, onyx, or similar), and possibly covered with a transparent quartz top layer. This creates a more robust stone, in which the play of color is enhanced by the dark background. High-quality Australian opals (especially black opals), however, are preferably processed as solid opals – each cut is individually tailored to the rough stone to maximize the play of color. The cutter (opal cutter) must be experienced in order to avoid stress cracks and to remove any sand spots (inclusions) from the stone.

Welo opals can also be cut, polished, and even faceted . In fact, cutters report that Ethiopian material is usually relatively easy to work with. It exhibits less stress when cut, and some pieces with very high transparency are faceted like other gemstones to create a sparkling play of light and color. Faceted Welo opals are visually reminiscent of fire opal or other transparent gemstones, but with the added opal shimmer. The majority of Welo opals are also cut as cabochons to emphasize the flat play of color. Due to their hydrophane properties, some opal cutters cut Welo rough stones very carefully using water cooling to avoid heat and desiccation shocks, and allow the stone to dry completely before final polishing.

Setting and jewelry design: This is where the differences in stability come into play. A precious opal can certainly be worn in a ring or bracelet (i.e. pieces of jewelry that are more exposed to shocks) – it is usually set in a protective bezel or prong setting. Nevertheless, experienced jewelers often set valuable opals with a closed base and delicate border to support the stone. Welo opals, on the other hand, many experts recommend Welo opals for pendants, earrings or brooches , where the risk of hard blows is lower. If a Welo opal is set in a ring, the setting should be particularly carefully crafted – e.g., a closed bezel setting that holds the stone all the way around and protects it from moisture from below. Since Welo opals absorb moisture, avoid open settings where the stone lies directly against the skin (sweat could penetrate). Welo opals are ideal for pendants or earrings, as this is where they develop their full color and are less exposed to stress.

Aesthetic use: Australian opals often embody timeless elegance – they can be seen in classic designs, high-quality individual pieces, and as highlights in platinum or gold jewelry. Black opals with intense color are often set as solitaires because they have enough “fire” on their own. Boulder opals with interesting patterns are often used by jewelry designers to create organic, artistic pieces that emphasize the stone’s natural form. Welo opals, with their youthful, colorful charisma, are popular in modern and boho-inspired designs ; they can be found in silver settings, combined with other colored gemstones or diamonds, or even strung as pearls/triplets in necklaces. Their comparatively lower cost also allows for experimentation in design and fashion: fashion designers value Welo opals as a trendy eye-catcher with opulent play of color .

Treatment and artificial enhancements: One aspect that should be of particular interest to experts: Australian opals are generally sold without any treatment – ​​what you see is their natural color. An exception are some lighter opals (e.g., Andamooka matrix opal), which have been artificially blackened through smoking or sugar-acid treatment to enhance the play of color. Caution is advised with Ethiopian opals: Natural black Welo opals are extremely rare; many dark-looking Ethiopian opals have been artificially blackened through smoking or coloring. Such treatments should be declared by the dealer. We, Alréon & Partner®, as well as reputable suppliers, transparently inform the customer whether an opal has been treated. 

5. Care instructions

Opals may be breathtakingly beautiful, but they require some care and attention to maintain their luster—especially the more delicate Welo opals. Here are the most important care instructions for both opal types:

• Contact with water and chemicals:
  Australian opals can be carefully cleaned with a soft, slightly damp cloth. Since they don't absorb water, brief exposure to moisture won't harm them – you can even rinse them with lukewarm water and a mild soap to remove fingerprints or dirt (followed by rinsing with clean water). However, harsh cleaning agents, acids, or alkalis should be avoided, as they could damage the polish. Ethiopian Welo opals should be cleaned dry whenever possible: it's best to just wipe gently with a soft, dry cloth. If necessary, you can use a slightly damp cloth, but the stone should not be soaked or left in water for extended periods. Under no circumstances should a hydrophane opal come into contact with soap, detergent, perfume, lotion, or similar products – it would absorb these liquids and thus lose its appearance. Therefore, always apply perfume and hairspray before wearing opal jewelry to prevent any residue from getting on the stone.
• Temperature and environment:
  Opals don't like sudden changes in temperature. They should be protected from extreme heat and cold . For example, remove your ring before entering a sauna or making snowballs in winter. Sudden changes in temperature can create internal tension . Direct, prolonged exposure to sunlight can dry out opals – Australian stones can lose some of their brilliance over time (some light-colored opals yellow slightly) , while Welo opals may develop cracks. So it's best not to leave them in direct sunlight for hours. A cool, shady place is best for storage.
• Humidity:
  For hydrophanous Welo opals, a certain amount of residual moisture is beneficial to prevent them from drying out completely. Do not store such opals in very dry air (e.g., near a heater in winter). A tried-and-tested method: Wrap the opal in a soft, slightly damp cloth or place a piece of damp cotton pad in the jewelry box – not soaking wet, just slightly damp. The closed box then creates a mildly humid microclimate. Australian opals don't need this, but it won't harm them either. Important: If a Welo opal does absorb water and becomes transparent, let it air dry naturally (depending on its size, this can take hours to a few days). Under no circumstances should you place it on a heater or in the sun to dry – this must be done gently to avoid stress.
• Mechanical stress:
  Opal jewelry should always be put on last and taken off first to minimize shock. Avoid scratches by storing opals separately from harder gemstones (preferably in a jewelry pouch or a separate compartment with soft padding). Do not use ultrasonic cleaners or steamers—the vibrations and heat could split opals or draw out moisture. For opal rings, check the setting regularly: If the stone becomes loose, have a jeweler adjust it before it falls out.
• Inspection:
  Welo opals, in particular, can show minimal changes over the years (e.g., a fine hairline crack that's barely visible to the naked eye). It doesn't hurt to examine the stone with a magnifying glass from time to time. If it becomes dull, a specialist can repolish it. However, slight cracks caused by drying out (crazing) cannot be reversed; in this case, prevention is key through careful care.

6. Market value and price development

There are clear price differences between Ethiopian and Australian opal stones in the opal market, mainly due to supply, demand and quality .

Australian opal —specifically, black opal from Australia—is among the most expensive gemstones. Due to the rarity of prime specimens (fiery color, large clear surfaces, dark body tone), top examples can fetch five-figure sums per carat. Australia has historically dominated the market and thus also determined prices . The prestige of Australian opals means that they are considered an investment : collectors and investors pay large sums, especially as certain mines become depleted. 

For example, in Lightning Ridge, high-quality opal nodules are becoming increasingly difficult to find – many old dumps are exhausted. Traders say the "days of cheap black opal" are over. In addition, mining costs in Australia are rising (strict mining regulations, high fees) , further limiting the available supply. 

The result: The supply of top-quality opals is declining, while demand remains high internationally – especially from the USA, Europe, and increasingly Asia. This tends to drive prices up . Anyone who buys a truly fine Australian opal today can generally expect this stone to retain its value or even increase over the years (naturally dependent on the global economy and fashion, but opals have a loyal collector community).

Welo opals (Ethiopia) came onto the market in large quantities from around 2008 and were initially surprisingly inexpensive . Suddenly, you could buy opalescent stones with intense colors for a fraction of the Australian price. This had to do with the abundant finds and Ethiopia's desire to gain a place in the opal market . In addition, there was a lack of trust at the beginning - many people wondered whether Ethiopian opals were as durable as Australian ones. Over time, it has been proven that good Welo opals are actually stable and beautiful, which has increased their acceptance. Today (as of 2025), the prices of Ethiopian opals range, depending on the quality, from a few euros per carat for simple material to several hundred euros per carat for outstanding pieces. This means that on average they are still considerably cheaper than comparable Australian opals . However, there are exceptions here too: An exceptional 50-carat Welo with a perfect honeycomb pattern and neon colors can fetch collector prices in the upper four-figure range – but even that would still be inexpensive compared to an Australian opal of similar beauty.

The price development of Welo opals has been interesting in recent years: Initially very cheap, prices rose slightly as the market recognized their quality. Then, in 2013, the Ethiopian government intervened with export restrictions (for a time, raw opals could no longer be exported unprocessed) . This led to a short-term shortage and rising prices until the market adjusted. A balance has now been reached: There is enough supply, but the best pieces have become rare and more expensive. Ethiopian opals are still considered a great value for money gem—a lot of color for your money. Their market value could increase in the long term if known deposits become exhausted or the government imposes strict export restrictions. For now, however, they are meeting a growing demand for affordable precious opals.

Stable value: Australian opals have always enjoyed trust; good black opals consistently fetch high prices at auctions. Famous pieces like the legendary "Flame Queen Opal" (263 carats, found in 1914) have been traded for millions of dollars. Such auction records underline the reputation of Australian opals as a blue chip among colored gemstones. Ethiopian opals lack such references – they have only been on the market for a short time and are not (yet) a classic auction item. However, dealers report that certain patterns (e.g., full-surface honeycomb in red) and large, clear Welo opals are being specifically sought after by collectors and are increasing in value.

In summary : Welo opals are budget-friendly and offer even the average jewelry buyer the chance to own an impressive opal piece. Australian opals are highly prized treasures . The current market situation shows that both have their place – Ethiopian opal has revitalized the market and opened up new buyer segments, while Australian opal maintains its luxury status .

Conclusion: Which opal for whom?

Both types of opal – Welo opals from Ethiopia and Australian opals – have their own unique charm. 

There is no clear winner , because choosing the “right” opal depends on your individual preferences and needs .

Do you want the most intense color play possible at an affordable price and are willing to pay a little extra attention to your gemstone's care? Then a Welo opal is ideal for you. These opals deliver spectacular rainbow colors and exciting patterns even at smaller sizes and are a perfect match for creative jewelry designs. For fashionable wearers, young people, or anyone simply fascinated by color, the Ethiopian opal offers a great introduction to the world of opals – without having to invest a fortune. 

In the end, one thing is clear: Both opal types are breathtakingly beautiful , and no photograph will ever fully capture their vibrant color magic. Whether you choose a Welo opal or an Australian opal depends on what's more important to you: the maximum explosion of color at an attractive price (Welo) or the legendary opal tradition with the highest level of exclusivity (Australia). 

Perhaps the best solution is to have both variations in your collection or jewelry collection. This way, you can wear and enjoy the perfect opal for every occasion and mood.

Closing quote: "The opal is a chameleon among gemstones – sometimes it appears playfully colorful, sometimes deep and mysterious. Whether from faraway Ethiopia or the red center of Australia: an opal captivates the eye and carries a piece of natural wonder within it." With this in mind, Alréon & Partner® wishes you much joy in discovering your personal opal treasures – may they enchant you as much as they have enchanted generations of opal lovers before you.

List of sources

1. Gemological Institute of America (GIA): Opal – A Play of Color.

2. International Gem Society (IGS): Ethiopian vs. Australian Opals – What's the Difference?

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4. Minerals.net: The Mineral Opal.

5. Smithsonian Magazine: Ethiopia's Welo Opals Challenge the Australian Monopoly.

6. National Jeweler: Opal Market Overview – Trends and Trade.

7. Mindat.org – Mineral Database: Opal Properties and Localities.

8. The Journal of Gemmology: Hydrophane Opals and their Behavior in Humid Environments.

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20. Alréon & Partner® internal specialist research and market observation 2024–2025.