Opal Rough- 11 g - (6)
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Selected by Antonio Rapisarda
Holds a master’s in chemistry with 25 years’ experience in minerals consulting.
Estimate € 150 - € 200
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A lot of six rough opals from Ethiopia, weighing 11 g in total (55 carats).
AI-assisted summary
Description from the seller
Lot consisting of 6 Ethiopian Rough Opals
55 Carats - 11Gr
Followed by description for single lots
1) LOTTO 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 a rough state (uncut and unpolished), preserving its original free-form shape (rough). The top part still shows a portion of light-colored clay-like or gypsum-like matrix rock.
* Color and Transparency: The base body of the stone has a warm honey-orange hue and is translucent. The most important aspect is the optical phenomenon visible at the center: a clear iridescent flash of neon green and yellowish from light diffraction inside the silica lattice of the stone.
* Weight Conversion: The 2 grams indicated correspond exactly to 10 carats (ct), the standard unit of measure used in the gem market.
Lot 2 rough opal 4Gr - 20 Carats
This specimen is a fragment of noble rough opal on rock matrix (Boulder Opal), presumably of Australian origin.
The value of this piece is higher than the previous ones due to its doubled weight (4g equals 20 carats) and the presence of rarer colors (purple/violet increases its value compared to only green).
Description and Visual Characteristics
* Morphology and Structure: It is a sample in natural rough state. The gem appears set within a massive mother rock (matrix) of dark brown color, clayey and ferruginous.
* Play-of-Color: Compared to the previous photo of the same piece, this closer-in and better-lit shot shows superior potential. On the top-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, semi-translucent texture, with gray-blue zones forming a base for the surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: It is a sample in natural rough state. The gem appears set within a massive mother rock (matrix) of dark brown color, clayey and ferruginous.
* Play-of-Color: Compared to the previous photo of the same piece, this closer-in and better-lit shot shows superior potential. On the top-right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Body of the Opal: The central vein crossing the rock has a milky and semi-glossy texture, with gray-blue zones forming the base for the surface iridescence.
Lot 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional fragment of noble fire opal hydro (hydrophane) rough, of Ethiopian origin (Welo).
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 lighting, intense multicolored iridescent flashes are clearly visible: fire red, neon orange, bright green and blue specks 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.
* Matrix Presence: The grayish porous host rock is confined almost entirely to the right edge and bottom. This means that nearly all of the weight consists of usable noble opal.
* Size/Weight Ratio: 2 grams equals 10 carats (ct). The measurements (1.8 cm height and less than 1 cm thick and wide) indicate an elongated shard shape.
Lot 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystalline noble opal rough (likely Welo Opal of Ethiopian origin).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense neon electric green flashes distributed as patches over the entire surface, accompanied by a definite and valuable orange/reddish blotch 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-translucent base, defined in gemology as white opal or clear crystal.
* Structure and Matrix: The piece is in natural rough state. It has a portion of sandy-beige mother rock confined to the back and 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.
Lot 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystal clear noble opal rough (Welo type, from Ethiopia). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite its small size, the stone shows a beautiful concentrated iridescence. A vivid green-neon flash shifts at the bottom, accompanied by blue electric specks and orange hues on the honeyed base.
* Body Tone: The base has a glassy, translucent, and crystalline texture (called crystal opal) ranging from transparent to pale amber-yellow at the center of the fragment.
* Structure and Matrix: The piece is completely natural rough. At the upper left edge, a small crust of dark brown mother rock is visible, while the right portion terminates with a very thin and transparent pointed shape.
* Size/Weight: The weight of 1 gram equals exactly 5 carats (ct). The form is very irregular, jagged, and shard-like.
Market Value Analysis
The price is slightly lower than the 1-gram piece due to its geometry:
* Jagged Form: The thin shard structure and the presence of sharp edges limit workable shapes. A potential cabochon cut would involve a high material loss, making it ideal mainly as a rough or educational collection piece.
* Green-Blue Vividness: The color quality remains very high; the blue-green reflections are saturated and respond well even under non-ideal light conditions, keeping the piece interesting for mineral enthusiasts.
Lot 6 Opal 5 Ct
This specimen is a fragment of noble crystal opal rough on matrix, clearly of Ethiopian (Welo) origin.
Gemmological Description and Characteristics
* Play-of-Color: On the predominantly glassy base, delicate but widespread iridescence points are seen. A blue electric speck stands out at the bottom and light orange and green reflections in the central section.
* Body Tone: The opal body is a transparent crystal opal, almost colorless and ice-like, differing from the previous pieces with a more amber base.
* Matrix and Structure: The ferruginous and dark brown mother rock concentrates at the top vertex, forming a clear cap over 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 on a nearly cube-shaped and compact form, given the nearly identical measurements between width (1.03 cm), height (1 cm) and depth (9 mm).
Total Lot of the 6 Ethiopian Opal - 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 between 170 and 310 euros, calculated by summing the individual pieces examined so far and considering the value premium of the higher-quality pieces with red and orange reflections.
View the images for proper evaluation.
We ship with protective packaging and tracking
Lot consisting of 6 Ethiopian Rough Opals
55 Carats - 11Gr
Followed by description for single lots
1) LOTTO 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 a rough state (uncut and unpolished), preserving its original free-form shape (rough). The top part still shows a portion of light-colored clay-like or gypsum-like matrix rock.
* Color and Transparency: The base body of the stone has a warm honey-orange hue and is translucent. The most important aspect is the optical phenomenon visible at the center: a clear iridescent flash of neon green and yellowish from light diffraction inside the silica lattice of the stone.
* Weight Conversion: The 2 grams indicated correspond exactly to 10 carats (ct), the standard unit of measure used in the gem market.
Lot 2 rough opal 4Gr - 20 Carats
This specimen is a fragment of noble rough opal on rock matrix (Boulder Opal), presumably of Australian origin.
The value of this piece is higher than the previous ones due to its doubled weight (4g equals 20 carats) and the presence of rarer colors (purple/violet increases its value compared to only green).
Description and Visual Characteristics
* Morphology and Structure: It is a sample in natural rough state. The gem appears set within a massive mother rock (matrix) of dark brown color, clayey and ferruginous.
* Play-of-Color: Compared to the previous photo of the same piece, this closer-in and better-lit shot shows superior potential. On the top-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, semi-translucent texture, with gray-blue zones forming a base for the surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: It is a sample in natural rough state. The gem appears set within a massive mother rock (matrix) of dark brown color, clayey and ferruginous.
* Play-of-Color: Compared to the previous photo of the same piece, this closer-in and better-lit shot shows superior potential. On the top-right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Body of the Opal: The central vein crossing the rock has a milky and semi-glossy texture, with gray-blue zones forming the base for the surface iridescence.
Lot 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional fragment of noble fire opal hydro (hydrophane) rough, of Ethiopian origin (Welo).
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 lighting, intense multicolored iridescent flashes are clearly visible: fire red, neon orange, bright green and blue specks 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.
* Matrix Presence: The grayish porous host rock is confined almost entirely to the right edge and bottom. This means that nearly all of the weight consists of usable noble opal.
* Size/Weight Ratio: 2 grams equals 10 carats (ct). The measurements (1.8 cm height and less than 1 cm thick and wide) indicate an elongated shard shape.
Lot 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystalline noble opal rough (likely Welo Opal of Ethiopian origin).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense neon electric green flashes distributed as patches over the entire surface, accompanied by a definite and valuable orange/reddish blotch 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-translucent base, defined in gemology as white opal or clear crystal.
* Structure and Matrix: The piece is in natural rough state. It has a portion of sandy-beige mother rock confined to the back and 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.
Lot 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystal clear noble opal rough (Welo type, from Ethiopia). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite its small size, the stone shows a beautiful concentrated iridescence. A vivid green-neon flash shifts at the bottom, accompanied by blue electric specks and orange hues on the honeyed base.
* Body Tone: The base has a glassy, translucent, and crystalline texture (called crystal opal) ranging from transparent to pale amber-yellow at the center of the fragment.
* Structure and Matrix: The piece is completely natural rough. At the upper left edge, a small crust of dark brown mother rock is visible, while the right portion terminates with a very thin and transparent pointed shape.
* Size/Weight: The weight of 1 gram equals exactly 5 carats (ct). The form is very irregular, jagged, and shard-like.
Market Value Analysis
The price is slightly lower than the 1-gram piece due to its geometry:
* Jagged Form: The thin shard structure and the presence of sharp edges limit workable shapes. A potential cabochon cut would involve a high material loss, making it ideal mainly as a rough or educational collection piece.
* Green-Blue Vividness: The color quality remains very high; the blue-green reflections are saturated and respond well even under non-ideal light conditions, keeping the piece interesting for mineral enthusiasts.
Lot 6 Opal 5 Ct
This specimen is a fragment of noble crystal opal rough on matrix, clearly of Ethiopian (Welo) origin.
Gemmological Description and Characteristics
* Play-of-Color: On the predominantly glassy base, delicate but widespread iridescence points are seen. A blue electric speck stands out at the bottom and light orange and green reflections in the central section.
* Body Tone: The opal body is a transparent crystal opal, almost colorless and ice-like, differing from the previous pieces with a more amber base.
* Matrix and Structure: The ferruginous and dark brown mother rock concentrates at the top vertex, forming a clear cap over 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 on a nearly cube-shaped and compact form, given the nearly identical measurements between width (1.03 cm), height (1 cm) and depth (9 mm).
Total Lot of the 6 Ethiopian Opal - 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 between 170 and 310 euros, calculated by summing the individual pieces examined so far and considering the value premium of the higher-quality pieces with red and orange reflections.
View the images for proper evaluation.
We ship 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.
