Opal Rough- 11 g - (6)
04
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18
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Starting bid
€ 1
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Selected by Georgia Foteinou
Holds BSc in geology and post-graduate qualifications in geochemistry.
Estimate € 180 - € 200
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Description from the seller
Lotto composed of 6 Rough Ethiopian Opals
55 Carats - 11Gr
Following is the description for individual lots
1) LOT 1 RAW 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 the rough state (un-cut and unpolished), preserving its original free form (rough). The top part still shows a portion of the light-colored clay/gypseous host 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 in the center: a bright iridescent flash of neon green and yellow generated 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 fragment of rough nobler opal on rocky 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 adds to the value compared to just green).
Description and Visual Characteristics
* Morphology and Structure: It is a sample in its natural rough state. The gem is set within a massive host rock (matrix) of dark brown, clayey, and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up, better-lit shot shows greater potential. On 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 and semi-glossy texture, with gray-blue zones forming the base for surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: It is a sample in natural rough state. The gem is set within a massive host rock (matrix) of dark brown, clayey, and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up, better-lit shot shows greater potential. On 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 and semi-glossy texture, with gray-blue areas forming the base for surface iridescence.
Lotto 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional fragment of noble hydrophane fire opal, 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 shows a full and vivid spectrum. Under this direct light, intense multicolored iridescent flashes are clearly visible: fire red, neon orange, bright green, and blue 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 almost the entire weight is attributable to usable noble opal.
* Size/Weight Ratio: 2 grams equal 10 carats (ct). The measurements (1.8 cm high and less than 1 cm thick and wide) indicate an elongated shard shape.
Lotto 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystal rough noble opal (very likely an Ethiopian Welo Opal).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense neon electric green flashes stand out, distributed as patches across the surface, accompanied by a defined orange/reddish blotch on the left side and yellow reflections on the right.
* Body Tone: Unlike the previous pieces with an 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 natural rough state. It presents a portion of sandy-beige host rock confined to the back and 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 crystallines noble opal rough (Welo type, origin Ethiopia). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite the small size, the stone displays a beautiful iridescence concentrated. A vivid neon green flash flashing in the lower part stands out, accompanied by blue electric specks and orange tints on the honeyed base.
* Body Tone: The base has a glassy, translucent, and crystalline texture (called crystal opal) varying from transparent to light amber-yellow in the center of the fragment.
* Structure and Matrix: The piece is completely natural rough. On the upper left edge a small crust of host rock (matrix) in dark brown is visible, while the right portion ends 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 Shape: The shard-like structure and the presence of sharp edges limit workability. A possible cut to cabochon would involve a very high material loss, making it ideal mainly as a rough or educational collectible piece.
* Vibrancy of Green-Blue: The color quality remains very high; blue-green and green reflections are saturated and respond well even in suboptimal lighting, keeping the piece interesting for mineral enthusiasts.
Lotto 6 Opal 5 Ct
This specimen is a fragment of noble clear crystal opal rough on matrix, clearly of Ethiopian origin (Welo).
Gemmological Description and Characteristics
* Play-of-Color: On the predominantly glassy base one notices delicate yet widespread iridescence. A blue electric speck is prominent in the lower part along with orange and green reflections in the central section.
* Body Tone: The opal body is of a crystal transparent type (crystal opal), almost colorless and ice-like, different from the previous pieces with a more amber base.
* Matrix and Structure: The ferruginous dark brown host rock is concentrated on 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 breaking.
* Proportions: The weight of 1 gram (5 carats) develops on an almost cubic and compact form, given the nearly identical dimensions of 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 ranges between 170 and 310 euros, calculated by summing the individual specimens examined so far and considering the value premium of pieces with higher quality, showing red and orange reflections.
Look at the images for proper assessment.
Shipped with protective packaging and tracking
Lotto composed of 6 Rough Ethiopian Opals
55 Carats - 11Gr
Following is the description for individual lots
1) LOT 1 RAW 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 the rough state (un-cut and unpolished), preserving its original free form (rough). The top part still shows a portion of the light-colored clay/gypseous host 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 in the center: a bright iridescent flash of neon green and yellow generated 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 fragment of rough nobler opal on rocky 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 adds to the value compared to just green).
Description and Visual Characteristics
* Morphology and Structure: It is a sample in its natural rough state. The gem is set within a massive host rock (matrix) of dark brown, clayey, and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up, better-lit shot shows greater potential. On 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 and semi-glossy texture, with gray-blue zones forming the base for surface iridescence.
Description and Visual Characteristics
* Morphology and Structure: It is a sample in natural rough state. The gem is set within a massive host rock (matrix) of dark brown, clayey, and ferruginous color.
* Play-of-Color: Compared to the previous photo of the same piece, this close-up, better-lit shot shows greater potential. On 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 and semi-glossy texture, with gray-blue areas forming the base for surface iridescence.
Lotto 3 Rough Opal 2Gr 10 Ct.
This specimen is an exceptional fragment of noble hydrophane fire opal, 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 shows a full and vivid spectrum. Under this direct light, intense multicolored iridescent flashes are clearly visible: fire red, neon orange, bright green, and blue 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 almost the entire weight is attributable to usable noble opal.
* Size/Weight Ratio: 2 grams equal 10 carats (ct). The measurements (1.8 cm high and less than 1 cm thick and wide) indicate an elongated shard shape.
Lotto 4 Rough Opal 1Gr - 5 Ct.
This specimen is a fragment of white crystal rough noble opal (very likely an Ethiopian Welo Opal).
Gemmological Description and Characteristics
* Play-of-Color: The stone shows a beautiful color contrast. Intense neon electric green flashes stand out, distributed as patches across the surface, accompanied by a defined orange/reddish blotch on the left side and yellow reflections on the right.
* Body Tone: Unlike the previous pieces with an 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 natural rough state. It presents a portion of sandy-beige host rock confined to the back and 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 crystallines noble opal rough (Welo type, origin Ethiopia). 1 gram (5 carats).
Gemmological Description and Characteristics
* Play-of-Color: Despite the small size, the stone displays a beautiful iridescence concentrated. A vivid neon green flash flashing in the lower part stands out, accompanied by blue electric specks and orange tints on the honeyed base.
* Body Tone: The base has a glassy, translucent, and crystalline texture (called crystal opal) varying from transparent to light amber-yellow in the center of the fragment.
* Structure and Matrix: The piece is completely natural rough. On the upper left edge a small crust of host rock (matrix) in dark brown is visible, while the right portion ends 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 Shape: The shard-like structure and the presence of sharp edges limit workability. A possible cut to cabochon would involve a very high material loss, making it ideal mainly as a rough or educational collectible piece.
* Vibrancy of Green-Blue: The color quality remains very high; blue-green and green reflections are saturated and respond well even in suboptimal lighting, keeping the piece interesting for mineral enthusiasts.
Lotto 6 Opal 5 Ct
This specimen is a fragment of noble clear crystal opal rough on matrix, clearly of Ethiopian origin (Welo).
Gemmological Description and Characteristics
* Play-of-Color: On the predominantly glassy base one notices delicate yet widespread iridescence. A blue electric speck is prominent in the lower part along with orange and green reflections in the central section.
* Body Tone: The opal body is of a crystal transparent type (crystal opal), almost colorless and ice-like, different from the previous pieces with a more amber base.
* Matrix and Structure: The ferruginous dark brown host rock is concentrated on 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 breaking.
* Proportions: The weight of 1 gram (5 carats) develops on an almost cubic and compact form, given the nearly identical dimensions of 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 ranges between 170 and 310 euros, calculated by summing the individual specimens examined so far and considering the value premium of pieces with higher quality, showing red and orange reflections.
Look at the images for 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.
