Quick answer: it can get wet without being destroyed, but you should avoid it. Most Ethiopian opal from the Welo (Wollo) region is hydrophane: porous enough to drink in water. When it soaks, it can turn transparent and lose its play-of-color for a while, then return to normal as it dries out slowly at room temperature. Keep it away from oils, lotions, and dyes, which can be absorbed permanently.
What “hydrophane” actually means
Opal is not a crystal. It is a mineraloid: tiny spheres of silica packed together with water trapped between them. Play-of-color happens when those spheres are uniform and stacked in neat rows, so they diffract light like a grating. In hydrophane opal, the spaces between spheres are open and connected, so the stone works almost like a sponge. Gemological reporting describes Welo opal as high-porosity, high-water-content hydrophane that “can absorb or lose water, affecting transparency and play-of-color when wet,” then regains its look as it dries (Rapaport).
The name comes from Greek: “water-revealing.” Some collectors enjoy dropping a piece in water to watch it go glassy, then watching the color slowly return over the following days.
The surprising part: it’s tougher than its reputation
Ethiopian opal was found near Wegel Tena in Wollo Province in 2008 and quickly flooded the market, which made buyers nervous about crazing (fine surface cracking). But lab testing found most specimens resisted crazing after repeated soaking and drying, and in one drop test, Wegel Tena opals survived a fall of over three feet onto concrete with no visible damage, while the Australian and Mezezo samples in the same test broke (Rapaport). That does not mean drop your ring; it means the fear outran the evidence.
What can go wrong
- Oils and dyes: Because the stone absorbs liquids, it can also absorb skin oil, perfume, or colored liquids. Some Ethiopian opal is deliberately smoke-treated to imitate black opal; no natural black opal has been reported from Ethiopia, so a jet-black Ethiopian opal deserves questions (Rapaport).
- Fast drying: Heat, direct sunlight, or a hair dryer on a soaked stone risks stress. Let it dry slowly.
- Ultrasonic cleaners: Never.
How to care for Welo opal
- Wipe with a soft, dry or barely damp cloth.
- Take opal jewelry off before swimming, showering, dishes, or applying lotion.
- If it goes clear or cloudy after getting wet, set it somewhere room-temperature and wait. Recovery can take from hours to several days depending on the piece.
- Store it away from harder stones; opal is only around 5.5 to 6.5 on the Mohs scale.
Bonus fact: there is opal on Mars
Opal only forms where water and silica-bearing rock interact. In December 2022, researchers reanalyzing NASA Curiosity rover data reported light-colored “halos” around fractures across Gale Crater that are likely rich in opal, confirmed at the Lubango drill site. The finding suggests water moved through Mars’s rocks more recently than thought, possibly within the last 2.9 billion years. Lead author Travis Gabriel called the fracture networks “likely chock-full of opal” (Live Science).
FAQ
Is all Ethiopian opal hydrophane? Most Welo material is. Opal from the older Mezezo (Shewa) deposit is different, often darker and in nodules.
What about Ethiopian fire opal? “Fire opal” describes an orange-to-red body color. Ethiopian fire opal usually comes from the same Welo deposits, so give it the same hydrophane care. Mexican fire opal is a different story; see Fire Opal: Named for Its Color, Not Its Flash.
Related reading
- Hardness isn’t the same as toughness
- How a cabochon is cut
- How to clean and store specimens without ruining them
Related pieces in the shop
Sources: Rapaport Magazine, “Ethiopian Opal”; Live Science on Gabriel et al., Journal of Geophysical Research: Planets (2022).
