Opal Rough- 11 g - (6)
Starting bid
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Expert
Selected by Antonio Rapisarda
Holds a master’s in chemistry with 25 years’ experience in minerals consulting.
Estimate € 220 - € 250
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Description from the seller
Lotto composed of 6 Rough Ethiopian Opals
55 Carats - 11Gr
Following is the description for single lots
1) LOT 1 ROUGH OPAL 2g-10Carats
The stone shown in the photo is a rough Ethiopian fire opal (also known as Welo Opal).
Description and Physical Characteristics
* Morphology and Cut: This is a mineral crystal in its rough state (un-cut and un-drilled), retaining its original free-form shape (rough). The upper part shows still a portion of the clay/gypseous colored light matrix rock.
* Color and Transparency: The base of the body of the stone has a warm honey-orange tone and is translucent. The most important aspect is the optical phenomenon visible at the center: a sharp iridescent flash of neon green and yellowish generated by the diffraction of light inside the silica lattice of the stone.
* Weight Conversion: The indicated 2 grams exactly correspond to 10 carats (ct), the standard unit of measure used in the gemstone market.
Lotto 2 rough opal 4Gr - 20 Carats
This specimen is a fragment of rough noble opal on rocky matrix (Boulder Opal), presumably of Australian origin.
The value of this piece is higher than the previous ones due to the doubled weight (4g equals 20 carats) and the presence of rarer colors (purple/violet increases the prestige compared to just green).
Description and Visual Characteristics
* Morphology and Structure: This is a sample in natural rough state. The gem is set within a massive mother rock (matrix) of dark brown, clayey and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up and better-lit frame shows higher potential. In the upper-right portion there is a vivid iridescent flash of neon green and purple/violet.
* The Opal Body: The central vein that crosses the rock has a milky and semi-glossy texture, with bluish-gray zones that form the base for the superficial iridescence.
Description and Visual Characteristics
* Morphology and Structure: This is a sample in natural rough state. The gem is set within a massive mother rock (matrix) of dark brown, clayey and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up and better-lit frame shows higher potential. In the upper-right portion there is a vivid iridescent flash of neon green and purple/violet.
* The Opal Body: The central vein crossing the rock has a milky and semi-glossy texture, with bluish-gray zones that form the base for the surface iridescence.
Lotto 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional piece of noble hydrofane fire opal rough, of Ethiopian origin (Welo).
It is the highest-quality piece among those shown so far.
Gemmological Descriptions and Characteristics
* Play-of-Color: The stone shows a full and vivid spectrum. Under this direct lighting, intense multicolor iridescent flashes are clearly visible: fire red, neon orange, bright green and bluish flecks in the lower part.
* Body-Tone: The opal body has a highly translucent crystalline base with amber and honey tones, typical of African fire opals with a glassy texture.
* Presence of Matrix: The grayish, porous mother rock is confined almost entirely to the right edge and bottom. This means almost all of the weight is noble opal usable.
* Size/Weight Ratio: 2 grams correspond to 10 carats (ct). The dimensions (1.8 cm height and less than 1 cm thickness and width) indicate an elongated shard shape.
Lotto 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystal rough noble opal (likely a Welo Opal of Ethiopian origin).
Gemmological Descriptions and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Prominent are intense electric neon green flashes scattered in patches across the surface, accompanied by a defined orange/reddish spot on the left side and yellow reflections on the right.
* Body-Tone: Unlike the previous pieces with amber base, this sample has a milky and semi-glossy base, defined in gemology as white opal or clear crystal opal.
* Structure and Matrix: The piece is in natural rough state. It has a portion of sandy beige mother rock confined at the back and on the upper right edge, while the main body is composed entirely of noble opal.
* Size/Weight: 1 gram equals exactly 5 carats (ct). The dimensions indicate a compact and slightly arched shard.
Lotto 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystalline noble opal rough (type Welo, origin Ethiopia). 1 gram (5 carats).
Gemmological Descriptions and Characteristics
* Play-of-Color: Despite its small size, the stone shows a beautiful concentrated iridescence. A vivid neon green flash stands out in the lower part, accompanied by blue electric specks and orange-tinted hues on the honeyed base.
* Body-Tone: The base has a glassy, translucent, and crystalline texture (crystal opal) ranging from transparent to pale amber yellow at the center of the fragment.
* Structure and Matrix: The piece is completely natural rough. On the upper left edge there is a small crust of dark brown mother rock, while the right portion ends in a very thin and transparent pointed tip.
* Size/Weight: The weight of 1 gram equals exactly 5 carats (ct). The shape is very irregular, jagged and shard-like.
Market Value Analysis
The price is slightly lower than the previous 1-gram piece due to its geometry:
* Jagged Shape: The shard-like structure and presence of sharp edges limit workability. A potential cabochon cut would entail a high material loss, making it ideal mainly as a raw or educational collection piece.
* Vibrancy of Green-Blue: The color quality remains very high; blue-green reflections are saturated and respond well even in non-ideal lighting, keeping the piece interesting for mineral enthusiasts.
Lotto 6 Opal 5 Ct
This specimen is a rough crystalline noble opal fragment on matrix, clearly of Ethiopian origin (Welo).
Gemmological Descriptions and Characteristics
* Play-of-Color: On the predominantly glassy base, delicate but widespread iridescence points are visible. A blue electric speck in the lower part and slight orange and green reflections in the central section stand out.
* Body-Tone: The opal body is of transparent crystal opal type, almost colorless and ice-like, different from the previous pieces which have more amber base.
* Matrix and Structure: The ferruginous dark brown mother rock is concentrated at the top vertex, forming a clear cap above the crystal. The structure shows several natural fractures and internal cleavage lines typical of rough material extracted by breaking.
* Proportions: The weight of 1 gram (5 carats) develops over a nearly cubic and compact shape, given the almost identical measurements between width (1.03 cm), height (1 cm) and depth (9 mm).
Total Lot of the 6 Ethiopian Opals - 11 grams - total 55 Carats
A total weight of 11 grams of Ethiopian opals corresponds exactly to 55 carats.
The overall commercial value for this entire rough lot is estimated to be between 170 and 310 euros, calculated by summing the individual pieces examined so far and considering the premium value of the higher-quality pieces with red and orange reflections.
Look at the images for a proper assessment.
Shipped with protective packaging and tracking
Lotto composed of 6 Rough Ethiopian Opals
55 Carats - 11Gr
Following is the description for single lots
1) LOT 1 ROUGH OPAL 2g-10Carats
The stone shown in the photo is a rough Ethiopian fire opal (also known as Welo Opal).
Description and Physical Characteristics
* Morphology and Cut: This is a mineral crystal in its rough state (un-cut and un-drilled), retaining its original free-form shape (rough). The upper part shows still a portion of the clay/gypseous colored light matrix rock.
* Color and Transparency: The base of the body of the stone has a warm honey-orange tone and is translucent. The most important aspect is the optical phenomenon visible at the center: a sharp iridescent flash of neon green and yellowish generated by the diffraction of light inside the silica lattice of the stone.
* Weight Conversion: The indicated 2 grams exactly correspond to 10 carats (ct), the standard unit of measure used in the gemstone market.
Lotto 2 rough opal 4Gr - 20 Carats
This specimen is a fragment of rough noble opal on rocky matrix (Boulder Opal), presumably of Australian origin.
The value of this piece is higher than the previous ones due to the doubled weight (4g equals 20 carats) and the presence of rarer colors (purple/violet increases the prestige compared to just green).
Description and Visual Characteristics
* Morphology and Structure: This is a sample in natural rough state. The gem is set within a massive mother rock (matrix) of dark brown, clayey and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up and better-lit frame shows higher potential. In the upper-right portion there is a vivid iridescent flash of neon green and purple/violet.
* The Opal Body: The central vein that crosses the rock has a milky and semi-glossy texture, with bluish-gray zones that form the base for the superficial iridescence.
Description and Visual Characteristics
* Morphology and Structure: This is a sample in natural rough state. The gem is set within a massive mother rock (matrix) of dark brown, clayey and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up and better-lit frame shows higher potential. In the upper-right portion there is a vivid iridescent flash of neon green and purple/violet.
* The Opal Body: The central vein crossing the rock has a milky and semi-glossy texture, with bluish-gray zones that form the base for the surface iridescence.
Lotto 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional piece of noble hydrofane fire opal rough, of Ethiopian origin (Welo).
It is the highest-quality piece among those shown so far.
Gemmological Descriptions and Characteristics
* Play-of-Color: The stone shows a full and vivid spectrum. Under this direct lighting, intense multicolor iridescent flashes are clearly visible: fire red, neon orange, bright green and bluish flecks in the lower part.
* Body-Tone: The opal body has a highly translucent crystalline base with amber and honey tones, typical of African fire opals with a glassy texture.
* Presence of Matrix: The grayish, porous mother rock is confined almost entirely to the right edge and bottom. This means almost all of the weight is noble opal usable.
* Size/Weight Ratio: 2 grams correspond to 10 carats (ct). The dimensions (1.8 cm height and less than 1 cm thickness and width) indicate an elongated shard shape.
Lotto 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystal rough noble opal (likely a Welo Opal of Ethiopian origin).
Gemmological Descriptions and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Prominent are intense electric neon green flashes scattered in patches across the surface, accompanied by a defined orange/reddish spot on the left side and yellow reflections on the right.
* Body-Tone: Unlike the previous pieces with amber base, this sample has a milky and semi-glossy base, defined in gemology as white opal or clear crystal opal.
* Structure and Matrix: The piece is in natural rough state. It has a portion of sandy beige mother rock confined at the back and on the upper right edge, while the main body is composed entirely of noble opal.
* Size/Weight: 1 gram equals exactly 5 carats (ct). The dimensions indicate a compact and slightly arched shard.
Lotto 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystalline noble opal rough (type Welo, origin Ethiopia). 1 gram (5 carats).
Gemmological Descriptions and Characteristics
* Play-of-Color: Despite its small size, the stone shows a beautiful concentrated iridescence. A vivid neon green flash stands out in the lower part, accompanied by blue electric specks and orange-tinted hues on the honeyed base.
* Body-Tone: The base has a glassy, translucent, and crystalline texture (crystal opal) ranging from transparent to pale amber yellow at the center of the fragment.
* Structure and Matrix: The piece is completely natural rough. On the upper left edge there is a small crust of dark brown mother rock, while the right portion ends in a very thin and transparent pointed tip.
* Size/Weight: The weight of 1 gram equals exactly 5 carats (ct). The shape is very irregular, jagged and shard-like.
Market Value Analysis
The price is slightly lower than the previous 1-gram piece due to its geometry:
* Jagged Shape: The shard-like structure and presence of sharp edges limit workability. A potential cabochon cut would entail a high material loss, making it ideal mainly as a raw or educational collection piece.
* Vibrancy of Green-Blue: The color quality remains very high; blue-green reflections are saturated and respond well even in non-ideal lighting, keeping the piece interesting for mineral enthusiasts.
Lotto 6 Opal 5 Ct
This specimen is a rough crystalline noble opal fragment on matrix, clearly of Ethiopian origin (Welo).
Gemmological Descriptions and Characteristics
* Play-of-Color: On the predominantly glassy base, delicate but widespread iridescence points are visible. A blue electric speck in the lower part and slight orange and green reflections in the central section stand out.
* Body-Tone: The opal body is of transparent crystal opal type, almost colorless and ice-like, different from the previous pieces which have more amber base.
* Matrix and Structure: The ferruginous dark brown mother rock is concentrated at the top vertex, forming a clear cap above the crystal. The structure shows several natural fractures and internal cleavage lines typical of rough material extracted by breaking.
* Proportions: The weight of 1 gram (5 carats) develops over a nearly cubic and compact shape, given the almost identical measurements between width (1.03 cm), height (1 cm) and depth (9 mm).
Total Lot of the 6 Ethiopian Opals - 11 grams - total 55 Carats
A total weight of 11 grams of Ethiopian opals corresponds exactly to 55 carats.
The overall commercial value for this entire rough lot is estimated to be between 170 and 310 euros, calculated by summing the individual pieces examined so far and considering the premium value of the higher-quality pieces with red and orange reflections.
Look at the images for a proper assessment.
Shipped with protective packaging and tracking
Details
Number of objects
6
Main mineral
Opal
Mineral form
Rough
Supplement
55 carats
Weight
11 g
Origin (region/city)
Italy
Country of origin
Ethiopia
Sold by
Disclaimer
It is believed that certain gemstones and minerals have beneficial health and spiritual properties. However, using or wearing gemstones or minerals does not mean that you can treat, cure or prevent any disease. Please consult your health care professional for information on health care issues and do not stop any medications or courses of treatment, without first consulting your health care professional. The use of gemstones or minerals as a wellness therapy is one of personal choice. While stones or crystals have been used historically to relieve or prevent symptoms, the objects sold on our website offer no guarantee of results. Therefore, Catawiki cannot guarantee or be held liable for the effectiveness of these objects sold herein.
It is believed that certain gemstones and minerals have beneficial health and spiritual properties. However, using or wearing gemstones or minerals does not mean that you can treat, cure or prevent any disease. Please consult your health care professional for information on health care issues and do not stop any medications or courses of treatment, without first consulting your health care professional. The use of gemstones or minerals as a wellness therapy is one of personal choice. While stones or crystals have been used historically to relieve or prevent symptoms, the objects sold on our website offer no guarantee of results. Therefore, Catawiki cannot guarantee or be held liable for the effectiveness of these objects sold herein.
