Opal Rough- 11 g - (6)
04
days
06
hours
48
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24
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Current bid
€ 10
Reserve price not met
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Selected by Antonio Rapisarda
Holds a master’s in chemistry with 25 years’ experience in minerals consulting.
Estimate € 150 - € 200
 | €10 |
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This lot contains six rough Ethiopian opals weighing 11 g in total, equivalent to 55 carats.
AI-assisted summary
Description from the seller
Lotto consisting of 6 Rough Ethiopian Opals
55 Carats - 11g
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: This is a mineral crystal in a rough state (un-cut and unpolished), preserving its original free form (rough). The top portion still shows a portion of the clay/gypseous light-colored matrix rock.
* Color and Transparency: The base body of the stone has a warm honey-orange hue that is translucent. The most important aspect is the optical phenomenon visible at the center: a clear iridescent flash of neon-green and yellowish color caused by the diffraction of light inside the stone’s silica lattice.
* Weight Conversion: The 2 grams stated correspond exactly 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 rock 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 just green).
Description and Visual Characteristics
* Morphology and Structure: This is a natural, rough state sample. The gem is mounted within a massive parent rock (matrix) of dark brown, clayey and ferruginous color.
* The Play-of-Color: Compared to the previous photo of the same piece, this closer, better-lit shot shows a higher potential. In the upper-right portion a vivid iridescent flash of neon green and purple/violet stands out.
* The Opal Body: The central vein running through the rock has a milky and semi-glossy texture, with gray-blue zones that form the base for the surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: This is a natural, rough state sample. The gem is mounted within a massive parent rock (matrix) of dark brown, clayey and ferruginous color.
* The Play-of-Color: Compared to the previous photo of the same piece, this closer, better-lit shot shows a higher potential. In the upper-right portion a vivid iridescent flash of neon green and purple/violet stands out.
* The Opal Body: The central vein crossing the rock has a milky and semi-glossy texture, with gray-blue zones forming the base for surface iridescence.
Lotto 3 Rough Opal 2g 10 Ct.
This specimen is an exceptional piece of noble, hydrophane rough fire opal from Ethiopia (Welo).
It is the finest quality piece among those shown so far.
Gemmological Description and Characteristics
* Play-of-Color: The stone exhibits a complete and vivid spectrum. Under this direct light, intense multicolor iridescent flashes are clearly visible: fire red, neon orange, bright green and bluish specks 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 grayish porous host rock is confined almost entirely to the right edge and the bottom. This means most of the weight is noble opal that can be used.
* Size/Weight Ratio: 2 grams equals 10 carats (ct). The measurements (1.8 cm height, less than 1 cm thickness and width) indicate an elongated shard shape.
Lotto 4 Rough Opal 1g - 5 Ct.
This specimen is a fragment of white crystal rough noble opal (very likely a Welo Opal of Ethiopian origin).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Prominent are intense neon green electric flashes distributed as patches over the entire surface, accompanied by a defined 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-glossy base, defined in gemology as white opal or clear crystal opal.
* Structure and Matrix: The piece is in natural rough state. It presents a sand-like beige host rock portion confined to the back and to the upper right edge, while the main body is entirely composed of noble opal.
* Size/Weight: 1 gram equals exactly 5 carats (ct). The dimensions indicate a compact, slightly arched shard.
Lotto 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystal noble opal rough (Welo type, Ethiopian origin). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite the small size, the stone shows a beautiful iridescence concentrated. A vivid neon green flash is seen in the lower part, accompanied by blue electric specks and orange shades over a honeyed base.
* Body Tone: The base has a glassy, translucent, and crystalline texture (crystal opal) varying from transparent to pale amber yellow at the center of the fragment.
* Structure and Matrix: The piece is completely rough natural. On the upper left edge a small crust of dark brown host rock is visible, while the right portion ends in a very slender and transparent point.
* 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 thin structure and the presence of sharp edges limit workability. An eventual cabochon cut would involve a very high material loss, making it ideal mainly as a rough or educational collection piece.
* Color Vivacity (Green-Blue): 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.
Lotto 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 iridescent points are visible. A blue electric speck in the lower part and light orange and green reflections in the central section stand out.
* Body Tone: The opal body is a transparent crystal opal, nearly colorless and ice-like, different from the previous pieces with a more amber background.
* Matrix and Structure: The ferruginous dark brown host rock is concentrated on the top vertex, creating a clear cap above the crystal. The structure displays several natural fractures and internal cleavage lines typical of rough material mined in broken chunks.
* Proportions: The 1 gram (5 carats) weight develops over a nearly cubical, compact shape, given the almost identical measurements of width (1.03 cm), height (1 cm) and depth (9 mm).
Total of Lotto 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 higher-quality pieces with red and orange reflections.
Look at the images for a correct evaluation.
Shipping is done with protective packaging and tracking.
Lotto consisting of 6 Rough Ethiopian Opals
55 Carats - 11g
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: This is a mineral crystal in a rough state (un-cut and unpolished), preserving its original free form (rough). The top portion still shows a portion of the clay/gypseous light-colored matrix rock.
* Color and Transparency: The base body of the stone has a warm honey-orange hue that is translucent. The most important aspect is the optical phenomenon visible at the center: a clear iridescent flash of neon-green and yellowish color caused by the diffraction of light inside the stone’s silica lattice.
* Weight Conversion: The 2 grams stated correspond exactly 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 rock 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 just green).
Description and Visual Characteristics
* Morphology and Structure: This is a natural, rough state sample. The gem is mounted within a massive parent rock (matrix) of dark brown, clayey and ferruginous color.
* The Play-of-Color: Compared to the previous photo of the same piece, this closer, better-lit shot shows a higher potential. In the upper-right portion a vivid iridescent flash of neon green and purple/violet stands out.
* The Opal Body: The central vein running through the rock has a milky and semi-glossy texture, with gray-blue zones that form the base for the surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: This is a natural, rough state sample. The gem is mounted within a massive parent rock (matrix) of dark brown, clayey and ferruginous color.
* The Play-of-Color: Compared to the previous photo of the same piece, this closer, better-lit shot shows a higher potential. In the upper-right portion a vivid iridescent flash of neon green and purple/violet stands out.
* The Opal Body: The central vein crossing the rock has a milky and semi-glossy texture, with gray-blue zones forming the base for surface iridescence.
Lotto 3 Rough Opal 2g 10 Ct.
This specimen is an exceptional piece of noble, hydrophane rough fire opal from Ethiopia (Welo).
It is the finest quality piece among those shown so far.
Gemmological Description and Characteristics
* Play-of-Color: The stone exhibits a complete and vivid spectrum. Under this direct light, intense multicolor iridescent flashes are clearly visible: fire red, neon orange, bright green and bluish specks 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 grayish porous host rock is confined almost entirely to the right edge and the bottom. This means most of the weight is noble opal that can be used.
* Size/Weight Ratio: 2 grams equals 10 carats (ct). The measurements (1.8 cm height, less than 1 cm thickness and width) indicate an elongated shard shape.
Lotto 4 Rough Opal 1g - 5 Ct.
This specimen is a fragment of white crystal rough noble opal (very likely a Welo Opal of Ethiopian origin).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Prominent are intense neon green electric flashes distributed as patches over the entire surface, accompanied by a defined 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-glossy base, defined in gemology as white opal or clear crystal opal.
* Structure and Matrix: The piece is in natural rough state. It presents a sand-like beige host rock portion confined to the back and to the upper right edge, while the main body is entirely composed of noble opal.
* Size/Weight: 1 gram equals exactly 5 carats (ct). The dimensions indicate a compact, slightly arched shard.
Lotto 5 Opal -1 Gr. 5Ct.
This specimen is a small shard of crystal noble opal rough (Welo type, Ethiopian origin). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite the small size, the stone shows a beautiful iridescence concentrated. A vivid neon green flash is seen in the lower part, accompanied by blue electric specks and orange shades over a honeyed base.
* Body Tone: The base has a glassy, translucent, and crystalline texture (crystal opal) varying from transparent to pale amber yellow at the center of the fragment.
* Structure and Matrix: The piece is completely rough natural. On the upper left edge a small crust of dark brown host rock is visible, while the right portion ends in a very slender and transparent point.
* 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 thin structure and the presence of sharp edges limit workability. An eventual cabochon cut would involve a very high material loss, making it ideal mainly as a rough or educational collection piece.
* Color Vivacity (Green-Blue): 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.
Lotto 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 iridescent points are visible. A blue electric speck in the lower part and light orange and green reflections in the central section stand out.
* Body Tone: The opal body is a transparent crystal opal, nearly colorless and ice-like, different from the previous pieces with a more amber background.
* Matrix and Structure: The ferruginous dark brown host rock is concentrated on the top vertex, creating a clear cap above the crystal. The structure displays several natural fractures and internal cleavage lines typical of rough material mined in broken chunks.
* Proportions: The 1 gram (5 carats) weight develops over a nearly cubical, compact shape, given the almost identical measurements of width (1.03 cm), height (1 cm) and depth (9 mm).
Total of Lotto 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 higher-quality pieces with red and orange reflections.
Look at the images for a correct evaluation.
Shipping is done 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.
