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 € 180 - € 200
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Description from the seller
Lotto consisting of 6 Rough Ethiopian Opals
55 Carats - 11 Gr
Followed by description for single lots
1) LOTTO 1 ROUGH OPAL 2g-10 Carats
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 the rough state (un-cut and un-burnished), preserving its original free form (rough). The upper part still shows a portion of the clay/gipsaceous light-colored host rock.
* Color and Transparency: The base of the stone has a warm honey-orange hue, translucent. The most important feature is the optical phenomenon visible at the center: a clear iridescent flash of neon green and yellowish-green caused by light diffraction within 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 gem market.
Lotto 2 rough Opal 4Gr - 20 Carats
This specimen is a rough noble opal fragment on a rocky matrix (Boulder Opal), presumably of Australian origin.
The value of this piece is higher than the previous ones due to the doubled weight (4 g equals 20 carats) and the presence of rarer colors (purple/violet increases the value compared to just green).
Description and Visual Characteristics
* Morphology and Structure: This is a natural rough specimen. The gem is set within a massive host rock (matrix) of dark brown, clayey and iron-rich color.
* Play-of-Color: Compared to the previous photo of the same piece, this closer and better-lit shot shows greater potential. In the upper-right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Body of the Opal: The central vein running through the rock has a milky and semi-glossy texture, with gray-blue zones serving as the base for the surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: This is a natural rough specimen. The gem is set within a massive dark brown, clay-rich, iron-rich host rock (matrix).
* Play-of-Color: Compared to the previous photo of the same piece, this closer and better-lit shot shows greater potential. In the upper-right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Body of the Opal: The central vein running through the rock has a milky and semi-glossy consistency, with gray-blue areas forming the base for the surface iridescence.
Lotto 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional piece of noble hydrophane rough fire opal, of Ethiopian (Welo) origin.
It is the highest-quality piece among those shown so far.
Gemmological Description and Characteristics
* Play-of-Color: The stone displays a full and vivid spectrum. Under this direct illumination, intense multicolored iridescent flashes are clearly visible: fire red, neon orange, bright green, and bluish specks at the bottom.
* Body Tone: The opal’s body has a highly translucent crystal base with amber and honey tones, typical of African fire opals with a glassy texture.
* Matrix Presence: The grayish, porous host rock is confined almost entirely to the right edge and bottom. This means nearly all of the weight is usable noble opal.
* Size/Weight Ratio: 2 grams correspond to 10 carats (ct). The measurements (1.8 cm high and less than 1 cm thick and wide) indicate an elongated shard-like shape.
Lotto 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystalline rough nob le opal (very likely an Ethiopian Welo Opal).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense neon green electric flashes appear as spots across the surface, accompanied by a distinct and valuable orange/reddish blot 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.
* Structure and Matrix: The piece is in natural rough state. It features a portion of sandy beige host rock confined on the back and the upper right edge, while the main body consists entirely of noble opal.
* Size/Weight: 1 gram equals exactly 5 carats (ct). The dimensions indicate a compact and slightly curved shard.
Lotto 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystalline noble opal rough (Welo type, Ethiopian origin). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite its small size, the stone shows a beautiful iridescence concentrated. A vivid shifting neon green flash stands out in the lower part, accompanied by blue electric specks and orange-tinged hues on the honeyed background.
* Body Tone: The base has a glassy, translucent, and crystalline texture (crystal opal) varying from transparent to light amber-yellow at the fragment’s center.
* Structure and Matrix: The piece is completely in rough natural state. On the upper-left margin is visible a small crust of dark brown host rock, while the right portion ends in a very thin, transparent pointed tip.
* Size/Weight: The weight of 1 gram equals exactly 5 carats (ct). The shape is highly 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 thin structure and the presence of sharp edges limit workability. A potential cabochon cut would involve a high material loss, making it ideal mainly as a raw or educational collector piece.
* Vivid Green-Blue: The color quality remains very high; the blue and green reflections are saturated and respond well even under non-ideal lighting, keeping the piece interesting for mineral enthusiasts.
Lotto 6 Opal 5 Ct
This specimen is a fragment of noble crystalline opal rough on matrix, clearly of Ethiopian (Welo) origin.
Gemmological Description and Characteristics
* Play-of-Color: On a mostly glassy base, delicate but widespread iridescence points are visible. A blue electric speck in the bottom section and light orange and green reflections in the central section stand out.
* Body Tone: The opal body is of crystal opal type, nearly colorless and ice-like, differing from the previous pieces with a more amber base.
* Matrix and Structure: The iron-rich dark brown host rock is concentrated at the top vertex, creating a clear cap above the crystal. The structure shows several natural fractures and internal cleavage lines typical of rough material extracted by breakage.
* Proportions: The 1 gram weight (5 carats) corresponds to a nearly cubic, compact shape, given the almost identical measurements of width (1.03 cm), height (1.0 cm), and depth (9 mm).
Total Lotto of 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 ranges from 170 to 310 euros, calculated by summing the individual specimens examined so far and considering the value premium of higher-quality pieces with red and orange reflections.
View the images for proper evaluation.
Shipped with protective packaging and tracking
Lotto consisting of 6 Rough Ethiopian Opals
55 Carats - 11 Gr
Followed by description for single lots
1) LOTTO 1 ROUGH OPAL 2g-10 Carats
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 the rough state (un-cut and un-burnished), preserving its original free form (rough). The upper part still shows a portion of the clay/gipsaceous light-colored host rock.
* Color and Transparency: The base of the stone has a warm honey-orange hue, translucent. The most important feature is the optical phenomenon visible at the center: a clear iridescent flash of neon green and yellowish-green caused by light diffraction within 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 gem market.
Lotto 2 rough Opal 4Gr - 20 Carats
This specimen is a rough noble opal fragment on a rocky matrix (Boulder Opal), presumably of Australian origin.
The value of this piece is higher than the previous ones due to the doubled weight (4 g equals 20 carats) and the presence of rarer colors (purple/violet increases the value compared to just green).
Description and Visual Characteristics
* Morphology and Structure: This is a natural rough specimen. The gem is set within a massive host rock (matrix) of dark brown, clayey and iron-rich color.
* Play-of-Color: Compared to the previous photo of the same piece, this closer and better-lit shot shows greater potential. In the upper-right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Body of the Opal: The central vein running through the rock has a milky and semi-glossy texture, with gray-blue zones serving as the base for the surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: This is a natural rough specimen. The gem is set within a massive dark brown, clay-rich, iron-rich host rock (matrix).
* Play-of-Color: Compared to the previous photo of the same piece, this closer and better-lit shot shows greater potential. In the upper-right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Body of the Opal: The central vein running through the rock has a milky and semi-glossy consistency, with gray-blue areas forming the base for the surface iridescence.
Lotto 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional piece of noble hydrophane rough fire opal, of Ethiopian (Welo) origin.
It is the highest-quality piece among those shown so far.
Gemmological Description and Characteristics
* Play-of-Color: The stone displays a full and vivid spectrum. Under this direct illumination, intense multicolored iridescent flashes are clearly visible: fire red, neon orange, bright green, and bluish specks at the bottom.
* Body Tone: The opal’s body has a highly translucent crystal base with amber and honey tones, typical of African fire opals with a glassy texture.
* Matrix Presence: The grayish, porous host rock is confined almost entirely to the right edge and bottom. This means nearly all of the weight is usable noble opal.
* Size/Weight Ratio: 2 grams correspond to 10 carats (ct). The measurements (1.8 cm high and less than 1 cm thick and wide) indicate an elongated shard-like shape.
Lotto 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystalline rough nob le opal (very likely an Ethiopian Welo Opal).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense neon green electric flashes appear as spots across the surface, accompanied by a distinct and valuable orange/reddish blot 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.
* Structure and Matrix: The piece is in natural rough state. It features a portion of sandy beige host rock confined on the back and the upper right edge, while the main body consists entirely of noble opal.
* Size/Weight: 1 gram equals exactly 5 carats (ct). The dimensions indicate a compact and slightly curved shard.
Lotto 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystalline noble opal rough (Welo type, Ethiopian origin). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite its small size, the stone shows a beautiful iridescence concentrated. A vivid shifting neon green flash stands out in the lower part, accompanied by blue electric specks and orange-tinged hues on the honeyed background.
* Body Tone: The base has a glassy, translucent, and crystalline texture (crystal opal) varying from transparent to light amber-yellow at the fragment’s center.
* Structure and Matrix: The piece is completely in rough natural state. On the upper-left margin is visible a small crust of dark brown host rock, while the right portion ends in a very thin, transparent pointed tip.
* Size/Weight: The weight of 1 gram equals exactly 5 carats (ct). The shape is highly 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 thin structure and the presence of sharp edges limit workability. A potential cabochon cut would involve a high material loss, making it ideal mainly as a raw or educational collector piece.
* Vivid Green-Blue: The color quality remains very high; the blue and green reflections are saturated and respond well even under non-ideal lighting, keeping the piece interesting for mineral enthusiasts.
Lotto 6 Opal 5 Ct
This specimen is a fragment of noble crystalline opal rough on matrix, clearly of Ethiopian (Welo) origin.
Gemmological Description and Characteristics
* Play-of-Color: On a mostly glassy base, delicate but widespread iridescence points are visible. A blue electric speck in the bottom section and light orange and green reflections in the central section stand out.
* Body Tone: The opal body is of crystal opal type, nearly colorless and ice-like, differing from the previous pieces with a more amber base.
* Matrix and Structure: The iron-rich dark brown host rock is concentrated at the top vertex, creating a clear cap above the crystal. The structure shows several natural fractures and internal cleavage lines typical of rough material extracted by breakage.
* Proportions: The 1 gram weight (5 carats) corresponds to a nearly cubic, compact shape, given the almost identical measurements of width (1.03 cm), height (1.0 cm), and depth (9 mm).
Total Lotto of 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 ranges from 170 to 310 euros, calculated by summing the individual specimens examined so far and considering the value premium of higher-quality pieces with red and orange reflections.
View the images for proper evaluation.
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.
