The Science of Difference: Australian Opal and Ethiopian Opal

# # The Science of Difference: Australian Opal and Ethiopian Opal in Mineralogical and Gemological Dimensions

Opal is an amorphous gem that has no exact crystal structure. It has a chemical formula of * * SiO2. NH2O * * is formed by the aggregation of 3-21% of silica and water. The aesthetic, called the Play of Color, is caused by the diffraction of light through small silica spherical particles neatly aligned within the mineral texture.

# # # 1.Geologic origin and mineral stability

* * Sedimentary Opal Australia: * * * Most of them were born in the Cretaceous sedimentary rock layer about 100 million years ago. Silica gel slowly penetrated and precipitated in shale or sandstone crevices, making the water of the structure very stable, including excellent density and tolerance for climate change, so it is classified as a mineral with a high degree of permanence.

* * The Ethiopian Opal (Volcanic Opal): * * Most of it comes from the Welo field, caused by the geological activity of this new era (Miocene) volcano and has a property called * * Hydrophane * * (Hydrophane) that makes it structurally highly porous, able to absorb water well.

# # # 2. Indicators of quality and beauty in gemology

The assessment of beauty and cumulative reliability has the following main factors:

* * * Background Color (Body Tone): * * Australian Opal Specifically * * Black Opal * * has a black or dark gray tone that helps drive the light to stand out.

* * * Brightness (Brightness): * * Ethiopian Opal stands out for its "Neon" lightness that is evident even in the dark.

* * * Pattern: * * A rare and sought-after pattern is * * Harlequin * *, often found in Australia.

# # # 3. Rarity and value in the cumulative market

* * * Opal Australia: * * Classified as * * "Very rare to rarest" * * and increasing in value every year.

* * * Ethiopian Opal: * * classified as * * "Medium Rare" * *.

# # # 4.Quality Improvement (Treatment) and Caution

* * * Smoke Treatment: * * Used to make Ethiopian opal black mimic

* * * Dyeing (Dyeing): * * Popular makes opal strangely colored.

# # # 5.Current market price assessment (unit: baht per carat)

* * * Australian Black Opal: * * 50,000 - 600,000 + baht.

* * * Ethiopian Welo Opal (Natural): * * 800 - 20,000 baht.

# # # 6.Story dimension and purpose in the collection

To * * "Heritage and Investment" * * Opal Australia is the best answer.

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Store pawn collection by Bunchong Tientong

6 Mar 2026