Opal Rough- 11 g - (6)
04
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€ 1
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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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Lot of six rough Ethiopian opals (Welo), total weight 11 g for 55 carats, with varying matrix, body tone and play‑of‑color as described.
AI-assisted summary
Description from the seller
Lotto consisting of 6 Rough Ethiopian Opals
55 Carats - 11Gr
Following is the 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: It is a mineral crystal in raw state (untreated and unpolished), preserving its original free form (rough). The upper part still shows a portion of the light-colored clay/gypseous rock matrix.
* Color and Transparency: The base 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 distinct iridescent flash of neon green and yellowish color caused by 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 measurement used in the gem market.
Lot 2 rough opal 4Gr - 20 Carats
This specimen is a rough noblOpal fragment 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 enhances its value compared to only green).
Description and Visual Characteristics
* Morphology and Structure: It is a natural rough specimen. The gem is set within a massive mother rock (matrix) of dark brown, clayey and ferruginous color.
* Play-of-Color: Compared to the preceding photo of the same piece, this closer, better-lit shot shows greater potential. In the upper right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Opal Body: The central vein that runs through the rock has a milky, semi-glossy texture, with gray-blue zones that serve as a base for surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: It is a natural rough specimen. 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 shot shows greater potential. In the upper right portion stands 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 forming the base for the surface iridescence.
Lot 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional fragment of noble hydroplane fire opal rough, 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 lighting, intense multicolor iridescent flashes are clearly visible: fire red, neon orange, bright green, and blue splashes at the bottom.
* Body Tone: The opal body has a highly translucent crystal base with amber and honey tones, typical of African fire opals with a glassy texture.
* Matrix Presence: The gray, porous host 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 equals 10 carats (ct). The measurements (1.8 cm in 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 crystal rough noble opal (most likely an Ethiopian Welo Opal).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense electric neon green flashes scattered as patches across the surface are accompanied by a distinct orange/reddish patch on the left side and yellow reflections on the right.
* Body Tone: Unlike the previous pieces with amber base, this sample has a milky, semi-glossy base, defined in gemology as white opal or clear crystal.
* Structure and Matrix: The piece is in natural rough state. It presents 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 curved shard.
Lot 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystallino rough noble opal (Welo-type, Ethiopia origin). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite the small size, the stone shows a beautiful concentrated iridescence. A vivid changing neon green flash stands out at the bottom, accompanied by blue electric specks and orange hues on the honey-colored base.
* Body Tone: The base has a glassy, translucent and crystalline (crystal opal) texture varying from transparent to pale amber yellow at the fragment’s center.
* Structure and Matrix: The piece is completely natural rough. At the upper left edge there is a small crust of dark brown mother rock, while the right portion ends with a very thin and transparent pointed tip.
* Size/Weight: 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 previous 1-gram piece due to its geometry:
* Jagged Form: The shard-like structure and the presence of sharp edges limit workability. A potential cabochon cut would result in a very high material loss, making it ideal mainly as a rough or educational collectible.
* Green-Blue Vividness: The color quality remains very high; blue and green reflections are saturated and respond well even in non-ideal lighting, 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 there are delicate but widespread points of iridescence. A blue electric speck is visible at the bottom, with slight orange and green reflections in the central section.
* Body Tone: The opal body is a transparent crystal opal, almost colorless and ice-like, different from the earlier pieces with a more amber base.
* Matrix and Structure: The ferruginous dark brown host rock is concentrated at the upper peak, creating a clear cap over the crystal. The structure shows several natural fractures and internal fissures typical of rough material broken during extraction.
* Proportions: The 1-gram weight (5 carats) develops on a nearly cubical and compact shape, with almost identical measurements in 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 between 170 and 310 euros, calculated by summing the individual specimens examined so far and considering the value premium of the higher-quality pieces with red and orange reflections.
Look at the images for a correct assessment.
Shipped with protective packaging and tracking
Lotto consisting of 6 Rough Ethiopian Opals
55 Carats - 11Gr
Following is the 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: It is a mineral crystal in raw state (untreated and unpolished), preserving its original free form (rough). The upper part still shows a portion of the light-colored clay/gypseous rock matrix.
* Color and Transparency: The base 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 distinct iridescent flash of neon green and yellowish color caused by 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 measurement used in the gem market.
Lot 2 rough opal 4Gr - 20 Carats
This specimen is a rough noblOpal fragment 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 enhances its value compared to only green).
Description and Visual Characteristics
* Morphology and Structure: It is a natural rough specimen. The gem is set within a massive mother rock (matrix) of dark brown, clayey and ferruginous color.
* Play-of-Color: Compared to the preceding photo of the same piece, this closer, better-lit shot shows greater potential. In the upper right portion stands a vivid iridescent flash of neon green and purple/violet.
* The Opal Body: The central vein that runs through the rock has a milky, semi-glossy texture, with gray-blue zones that serve as a base for surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: It is a natural rough specimen. 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 shot shows greater potential. In the upper right portion stands 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 forming the base for the surface iridescence.
Lot 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional fragment of noble hydroplane fire opal rough, 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 lighting, intense multicolor iridescent flashes are clearly visible: fire red, neon orange, bright green, and blue splashes at the bottom.
* Body Tone: The opal body has a highly translucent crystal base with amber and honey tones, typical of African fire opals with a glassy texture.
* Matrix Presence: The gray, porous host 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 equals 10 carats (ct). The measurements (1.8 cm in 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 crystal rough noble opal (most likely an Ethiopian Welo Opal).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense electric neon green flashes scattered as patches across the surface are accompanied by a distinct orange/reddish patch on the left side and yellow reflections on the right.
* Body Tone: Unlike the previous pieces with amber base, this sample has a milky, semi-glossy base, defined in gemology as white opal or clear crystal.
* Structure and Matrix: The piece is in natural rough state. It presents 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 curved shard.
Lot 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystallino rough noble opal (Welo-type, Ethiopia origin). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite the small size, the stone shows a beautiful concentrated iridescence. A vivid changing neon green flash stands out at the bottom, accompanied by blue electric specks and orange hues on the honey-colored base.
* Body Tone: The base has a glassy, translucent and crystalline (crystal opal) texture varying from transparent to pale amber yellow at the fragment’s center.
* Structure and Matrix: The piece is completely natural rough. At the upper left edge there is a small crust of dark brown mother rock, while the right portion ends with a very thin and transparent pointed tip.
* Size/Weight: 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 previous 1-gram piece due to its geometry:
* Jagged Form: The shard-like structure and the presence of sharp edges limit workability. A potential cabochon cut would result in a very high material loss, making it ideal mainly as a rough or educational collectible.
* Green-Blue Vividness: The color quality remains very high; blue and green reflections are saturated and respond well even in non-ideal lighting, 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 there are delicate but widespread points of iridescence. A blue electric speck is visible at the bottom, with slight orange and green reflections in the central section.
* Body Tone: The opal body is a transparent crystal opal, almost colorless and ice-like, different from the earlier pieces with a more amber base.
* Matrix and Structure: The ferruginous dark brown host rock is concentrated at the upper peak, creating a clear cap over the crystal. The structure shows several natural fractures and internal fissures typical of rough material broken during extraction.
* Proportions: The 1-gram weight (5 carats) develops on a nearly cubical and compact shape, with almost identical measurements in 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 between 170 and 310 euros, calculated by summing the individual specimens examined so far and considering the value premium of the higher-quality pieces with red and orange reflections.
Look at the images for a correct 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
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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.
