Opal Crystal - Height: 70 mm - Width: 60 mm- 251 g - (1)

Ethiopian rough opal – 251 g / approx. 1.255 ct – large translucent opal mass with red-green play-of-color and natural matrix

Offered is an exceptionally large rough opal from Ethiopia, weighing 251 grams, corresponding to about 1.255 carats.

The piece is in its natural rough state and shows large cohesive translucent to partially distinctly light-permeable opal areas. Particularly striking are the warm honey, amber and orange coloring as well as the play-of-color visible at various points.

Depending on the viewing angle and incident light, especially vivid red and green color reflections emerge.

Color and color play

The body color varies within the stone from lighter honey-colored and yellowish areas through amber and orange to stronger cognac- and reddish-brown sections.

Within this base color, the rough opal shows pronounced color play at numerous points.

In appropriate lighting, light penetrates far into the stone. This makes internal structures, different color zones, and deeper color play visible.

Some areas appear particularly light-transmissive in backlighting. However, the transparency is not uniform across the entire piece. In addition to clearer areas there are cloudier zones, natural inclusions, matrix remnants, and internal crack and fracture structures.

Color play in backlighting

Some of the photographs were deliberately taken against the sunlight.

This makes the internal color play particularly clearly visible. Especially the green and red color zones stand out very strongly under this lighting.

This appearance depends on the viewing angle and the light source and may appear noticeably more restrained under normal room lighting.

Natural matrix / host rock

The original host rock or natural matrix is partially preserved.

The beige-gray to brownish matrix areas are especially located on various outer and edge areas of the piece. On other sides, large cohesive opal surfaces are exposed.

Of particular interest is the natural transition between matrix and transparent or translucent opal.

The matrix was intentionally not completely removed. The stone thus continues to document its natural formation and embedding structure.

On one side there is a larger cohesive matrix area with numerous natural depressions and cavities. This side has also been photographed in detail.

Natural inclusions, cracks and fracture structures

The rough opal possesses numerous structures characteristic of an untreated natural specimen.

Notably visible are:

* natural matrix portions
* mineral inclusions
* natural depressions and hollows
* internal crack and fracture lines
* fissures
* natural break surfaces
* varying transparency and opal zones

Several crack and fracture lines run through the translucent opal areas and are clearly visible in the photographs.

Photographs – important note

The photographs depict the actually offered specimen from numerous different perspectives and, in part, in close-up/macro.

The shots were taken in natural direct sunlight.

Some photographs were additionally taken against the sun to make transparency, interior structures, and the existing color play more visible.

The stone was moistened with water for the photographs.

Wetting increases surface luster and can, especially with hydrophane opal, also affect transparency and optical appearance. Direct sunlight and backlighting also cause the play-of-color to appear significantly stronger.

The photographs therefore expressly document the appearance of the moistened stone in direct sunlight or partially in backlighting.

Note on Ethiopian opal and hydrophobic properties

A large portion of Ethiopian opals can possess hydrophobic properties. Hydrophobic opal is porous and can absorb water. This can temporarily change transparency and optical appearance.

For Ethiopian Wollo opals, this behavior is gemmologically well documented. Studies by the Gemological Institute of America (GIA) show that water absorption in hydrophobic opal can alter transparency and that the reaction within a single rough piece, due to varying porosity, need not be uniform.

However, the present stone has not been gemmologically tested for hydrophobic properties. Nor is there gemological determination of a specific deposit within Ethiopia.

For this reason, no particular regional origin within Ethiopia and no specific hydrophobic classification are warranted.

Details about the piece

Mineral: Rough opal
Origin: Ethiopia
Weight: 251 g
Carat weight: approx. 1.255 ct
Condition: natural rough state
Matrix/host rock: present, partially larger natural matrix areas
Transparency: large translucent, partially clearly light-permeable areas
Body color: honey yellow, amber, orange, cognac to reddish-brown
Color play: especially red, green, orange and yellow; locally additional hues
Natural features: matrix, inclusions, hollows, cracks, fissures and fracture lines.

The sale is by private individual.

All information has been provided to the best of my knowledge and based on my own observations and available information. I am a private seller and not a gemological institute.

Therefore I do not assume any warranty for the accuracy of mineralogical or gemological determinations, origin classifications, or other information, insofar as this is legally permissible. Despite careful description, unintentional errors or deviations in individual details cannot be completely excluded.

The photographs are expressly part of the description. Please review all images carefully. They document in particular color, matrix, inclusions, hollows, natural cracks, fracture lines, surface structure and the overall condition of the offered piece.

It should be noted that the photographs show the moistened stone under direct sunlight and partially in backlighting.

The item is sold in the condition shown in the photographs.

This is a private sale with exclusion of warranty for defects, where legally permissible. No guarantees and no returns.